Reptile
and some rush down oriented characters can become to much for him.
okay, I agree rush down characters with fast runjabs can get reptile caught up very easily. Kabal is an easy target for reptile, but if he gets stuck in rubjabs, you can have some really bad times getting out of it.
but on the other side, he is not so great against characters that can teleport behind him. A Teleporting character can cause Hell for Reptile. It can shut down his Forceball Spam completely, but watch out for him Blocking.
Okay, I agree with this, and disagree with it. Tele punches fuck up the forceball traps, so real reptile players WON'T do forceballs traps, they're throw an occasional one to keep you off guard, but they'll lay off, they'll do one forceball, pretend to be doing a second but will really block you and punish you. I ALWAYS counter pick reptile with teleports. Anyone who plays ermac, or hsmoke knows how easy it is to react with a tele punch. If you can scout out when they do that, or just know what pressures people into doing that, you can just fuck them up with 2 dash punch punishers and it's over.
Tell people to be scared of his inf, but you'll never see the whole thing be done to you unless your jax usub or sindel. BARELY any players can hit the inf vs male ninjas and stryker. Most can do 3-4 dashes resulting in 50%+
It will lead into another infinite attempt. His Slide is only useful at close range, so watch out for it as well. Sheeva can Get an Uppercut after her throw against Reptile. Jade can cause all sorts of new hell for Reptile and is probably the best counter for Reptile. Her Projectile Pass move completely negates forceball spam, and her awkward female ninja properties are difficult to Juggle. Human Smoke, Scorpion, Sektor, Ermac, and Robo Smoke are probably the best teleporting characters to use against Reptile.
I don't get how blocking sets up infinites, except for when you come out of noewhere with his popup. I like to play with reptile vs. jade too, even though it's a decent counterpick and arguably the best, picking jade just means a new stragedy for reptile.
Anyway, that's just my two cents reptiles my guy, so he's the only one I might be able to give some actual advice on.
Edit: Oh yeah, and just like dreamcatcher said the inf possibilities on sindel usub and jax should lower their advantages, usub is a really good fight vs reptile, but if hes set up in the inf (which is hard to find the exact positioning) its over.