(Potentially needs an overhaul but has some good info from old page so it has been transferred here)
Match-ups
Serious Advantage Match-ups
Alex has no match-ups where he is at a serious advantage
Advantage Match-ups
Q
Headbutt works well against Q, so use it often.
Mixup your "Big Guy" pokes: twd.FP,
.Flash Chop, st., twd..
After your pokes, throw in empty parries to catch Q's rush punches.
Hugo
Poke with towards.FP (the lariat)/towards.//Headbutt. st. beats Hugo's st.. Also try poking every so often with amp.Flash Chop from just outside Hugo's 360 range.
You can't headbutt a dizzied Hugo.
Twelve
Anti-air with EX-Knee Grab.
Try to catch him with air-to-air j., j.FP, j.
to reset him, then dash up and mixup with either kara throw, jab powerbomb, st. or st. xx EX-Flash Chop. Try a plain EX-Flash Chop after dashing, too, since it's low risk. You can also try charge partitioned trickery, like dash stomp or dash 
/EX-Slash Elbow.
Sean
Punish blocked cr.FK with EX-Slash Elbow.
Punish blocked shoto cr. with SAII or SAI (reversal timing required, and must be very close to opponent)
Fair Match-ups
Remy
Remy has one of the shortest stun bars in the game, so your goal should be to exploit that. Headbutt! Keep the pressure on and make sure you can parry his LOV's and Flash Kicks to get inside.
Blocked Flash Kicks (any variety) can be punished with a headbutt.
Alex
Don't get too predictable with your stomp setups. If you're playing a guy and you smell stomp, unless you know which way it's going (crossup or not), you can use EX Stomp and it will beat out the regular stomp.
Necro
Do not blindly use EX-Slash Elbow once he gets meter, since he has one of the fastest supers (SAIII) in the game and can punish a blocked one. You can, however, still use normal Slash Elbows if you space them properly ( version only). You want to hit with it so you can block any retaliation if the Slash Elbows is blocked.
Necro's long limbs parried at a distance are perfect for twd.FP.
Immediately twd.FP Necro if you see him jump from close up. Also, learn how to red parry the second hit of his drills, then punish with st. xx EX-Knee Grab.
Disadvantage Match-ups
Yun
Random stomp sometimes helps against activated Yun trying for the command throw.
Stay just out of Yun's dash range. In my experience, forcing Yun to come after you works the best, since you can react accordingly. In short, I guess, keep-away is good.
When a Yun/Yang dives on u throw out a st. when they're going to jump out again, if the dive kick is too deep you can throw them. Also, for people who like to run away and charge with crouching strong usually you can throw out an EX-Slash Elbow, its so fast a lot of times I notice it surprises the opponent. And even if its blocked its safe vs yun/yang. Abuse the jab powerbomb on Yun's wakeup since he has very few good wakeup options.
When Yun/Yang tries to either throw, command grab, or hit with st. launcher, counter with the backward-karamp.Flash Chop (kara with Roundhouse Kick to move backwards instead of forwards). This will move you out of throw/launcher range and nail Yun/Yang with a Flash Chop --> German Suplex or combo of your choice.
Learn how to red parry the second hit of Yun's j.
--> j.FP target combo. If you successfully red parry the j.FP, hit a quick st. xx SAII
Ken
When playing footies, stay out of his c. range at all times. Thankfully alex's c.mp & s. go over ken's c., so use that;However, a good ken will wait for you to whiff the move first so they can walk foward c.xxSAIII.
So, when you poke out a move, ALWAYS make it hit, even if it's blocked because alex has slow recover time if missed. It's ken's c.mp, s.mp that you have to worry about, that shit will just out prioritize most of the time.
It's not the safest thing, but f.fp is good move when at about jab length away because it will hit ken crouching too. But as i said it ain't the safest thing so I only use it when ken has no super. Same goes for alex's c.fk, it's good to use it at sweep distance, but if whiffed it's a long recovery time.
When ken has no meter, you can throw out c.mp & s. without fear of missing & taking bing damage so keep the pressure on ken as long as you can. You can't out prioritize ken, but since alex has longer limbs than ken just stay right outside his c.fk/s.fk range.
The best thing to do is wait for ken to whiff a move, then go for an attack. You have 3 or 4 options or so.
1. Punish a whiffed move with alex's c.mp s. c.fk. The problem with this, is that ken has like, little to no reaction time off his whiffed moves so you gotta be quick, like you just gotta know it will miss & hit ASAP off reaction.
2.Dash foward kara-throw/ powerbomb. I like the kara-throw better, i believe it comes out faster the powerbomb. Plus, this gives alex that momentum to start mixing up his high/low/grab game. This is also a good tatic to do out of the blue too, but if they have a super it's kinda of a gamble.
3.Jump towards them. The jump game brings a whole new set of options, so i'm only going to hit a couple of them. A lot of kens moves will react before you get there so ithe safest thing to do is empty jump just to keep the pressure on.
Empty jump:throw, powerbomb, c.->kara-throw, ect. If you jump in you can tick throw afterwards. Or jump in late with amp so that it misses & you can land throw. But since ken has his SRK it's safest to just empty jump just un case so you can parry.
4.EX Elbow. Even from half the screen this move will punish people who just throw out random attacks. If ken has no meter you are completely safe, but it can be punished with his SAIII, unlike his .elbow which is safe even from super. Also, sharge down as soon as you ex elbow so if ken moves at all you can stomp him.
Random Tips -S.FP will tie out with SRK -EX Stomp will hit every time if ken throws a fireball -F.FP will beat ken's air-hurricane kick
Makoto
Since she likes to dash around a lot, throw out random (unpredictable) cr. or st. every so often to catch her. Also, if you space yourself correctly, you could fish for SAII by hitting st. and buffering the super...similar to Dudley's st.FK xx EX-MGB empty buffering. This is risky though, because if you're too far away from her when you connect with the st., the grab at the end of the super will wiff.
They love to jab tick into karakusa. Doesn't matter what the tick is, if you see it, st.FK (Das Boot!) pulls you out of grab range and deals in pain.
Dudley
Poke with towards.FP (the lariat)/towards.//Headbutt. Try to anti-air Dudley the split second you see him leave the ground with a well placed towards.FP. You can also try to poke Dud with.Flash Chops (you'd be surprised!)
ONLY safe shoulder dash against kensa3/chunsa2/necrosa1/3/dudleysa3/elenasa2 is a .Slash Elbow... all others are reversible by super.
A blocked SA3 from Dudley keeps you at st. strong xx EX slash elbow range. It is a lifesaver if he's got you in the corner.
st. xx EX Slash Elbow punishes any MGB (EX or not).
Yang
If yang stops his EX slashes at about three or four, meaning you were blocking til then, free headbutt.
When Yun/Yang tries to either throw, command grab, or hit with st. launcher, counter with the backward-karamp.Flash Chop (kara with Roundhouse Kick to move backwards instead of forwards). This will move you out of throw/launcher range and nail Yun/Yang with a Flash Chop --> German Suplex or combo of your choice.
Akuma
Punish blocked cr.FK with EX-Slash Elbow.
If you block any variation of Akuma's spinning kick you can succesfully reversal into a guaranteed super as long as you're not slow as fuck. You catch him recovering.
Punish blocked shoto cr. with SAII or SAI (reversal timing required, and must be very close to opponent)
Urien
Urien's wakeup options are limited, so you should meaty jab powerbomb him a few times to keep him on his toes, then mixup st. xx SAII.
Urien can't use his normal juggles on Alex since Alex's floating/weight properties are different than the rest of the cast. This can be a good advantage.
Against Urien, cr. is a godsend. It's free damage against a blocked tackle.
Meaty st.FP should stuff anything he does on wake-up.
If an Aegis Reflector is in front of you and Urien is walking up, headbutt. The hand goes through the reflector and will grab Urien through it.
Ryu
Punish blocked cr.FK with EX-Slash Elbow.
Block Hurricane Kicks standing so you can punish with with or Powerbomb. You can also duck the kick and get up between the hits and choke or Backdrop him.
Punish blocked shoto cr. with SAII or SAI (reversal timing required, and must be very close to opponent)
Oro
Keep to the ground against Oro. A single parry can send you into an easily achievable unblockable set up.
Headbutting parried normals is a good idea against Oro.
Oro's jump-ins do not angle very well. They're good air to air but air to ground cr.
will beat them everytime. st. as an anti-air against Oro is also good for similar reasons. Cancel st. into EX-Knee Grab.
Ibuki
cr.FP (the rising shoulder tackle) immediately when you see Ibuki leave the ground, which she likes to do often. If you hit with the cr.FP early so it only connects once instead of twice, you can follow up with a quick FK.Knee Grab.
cr. FP, out-prioritizes ALL of Ibuki's air normals and kunai except for an early j.FK. Hence the reason it's your best friend.
When she jumps in, she usually goes for a 2-hit air target combo, so be prepared to do a bunch of double parrying. Punish with st. xx EX-Knee Grab when you get an opportunity.
Alex's twd.FP can sometime knock Ibuki's kunai out of the air if Ibuki jumps and throws the kunai...this takes good timing.
Meet her in the air with an early j. or j....these are great air-to-air normals. Try to stay off the ground for the entire match since Ibuki wants you grounded to land her cross-up into crazy stun combos.
If she gets a launch combo on you (like jab-strong-c.roundhouse-roundhouse or something like that), if you're quick enough, EX-Knee Grab.
Her jab-strong block chains leave you without a lot to do so block low and if you see her getting in close for a throw attempt, immediately Stomp. It's easy to see too, because it's the moment she's not jabbing.
When she performs an SAI to chip you away, you SHOULD try to UOH or just jump to take minimum damage. The jump will cause you to get hit by like three kunai and then you'll drop to the ground.
You can Knee Grab Ibuki out of SAI. Even if you get hit, you take minimal damage because you're airborne.
If you block Ibuki's close FK, and she doesn't super jump cancel, it's a free headbutt.
Elena
ONLY safe shoulder dash against kensa3/chunsa2/necrosa1/3/dudleysa3/elenasa2 is a .Slash Elbow... all others are reversible by super.
cr.FP (the rising shoulder tackle) immediately when you see Elena leave the ground. If you hit with the cr.FP early so it only connects once instead of twice, you can follow up with a quick FK.Knee Grab.
When she jumps in, she usually goes for a 2-hit air target combo, so be prepared to do a bunch of double parrying. Punish with st. xx EX-Knee Grab when you get an opportunity.
parrying her Mallet Smash (arch kick), the two hit one, allows for a choke/sleeper hold, or german suplex as a follow-up.
Serious Disadvantage Match-ups
Chun-Li
Do not blindly use EX-Slash Elbow once she gets meter, since she has one of the fastest supers (SAII) in the game and can punish a blocked one. You can, however, still use normal Slash Elbows if you space them properly. You want to hit with it so you can block any retaliation if the Elbow Slash is blocked.
Whenever Chun doesn't have a super charged, rush her down...this is your shot at dealing some damage before she becomes extremely dangerous. So, at the start of the first round, be aggressive. Try some cr.FK outside of her cr. range to trip her up. Throw in some headbutts while playing the footsie game with her. Tick powerbomb with j., or early j.FP --> land then jab.powerbomb.
Once she gets meter, you'll need to be less aggressive and more tricky since one little mistake can cost you the round easily. Try to get a knockdown with charge partitioned dashing stomps. Carefully poke with far. or towards.(the chop). Empty jump-in and mix-up charge partitioned stomps/kara throws/ xx EX Flash Chop/low parry SGGK technique. Parry her pokes from a distance if you can, and retaliate with the headbutt for nice stun.
ONLY safe shoulder dash against kensa3/chunsa2/necrosa1/3/dudleysa3/elenasa2 is a .Slash Elbow... all others are reversible by super.