So far from what i’ve tried, these are a few common things that U1 can counter on the first hit (the knock up part). Take note that these are from about mid screen and are some things people like to spam online or use to get in close. The first hit has no invincibility frames, so if you do it at point blank, you may find yourself losing or trading with some of these.
-Your Ultra meter gets used up on your way to the wall, so if you trade or get knocked out of that first hit you lose your ultra.
-You cannot combo into U1(or U2) off an anti air lk ST.
-I have not tried the EX versions or Ultras (you prolly wont find too many midscreen ultras anyway unless it’s to try and kill you with chip)
Blanka Ball (but Rainbow ball beats it)
Bison Scissor Kick (but Psycho crusher beats it)
Grounded Hurricane kicks
Gouken Palm strike
Cannon Drill (loses to it if you do it too late)
Chicken Wing (Loses to it if you do it too late)
Balrog dash punch (can go through his headbutt if done late, but no point in doing that when you can just wait a sec longer for the extra 30 damage)
I also noticed that sometimes if your timing is off, you may go right over the person, but if their move travels far or high enough, they end up falling into perfect range for the later hits of U1 (Bison’s Pycho crusher is iffy right now, sometimes it hits you out of your ultra, sometimes it doesnt).
If someone wants to add to the list, i’ll update this first post. I haven’t done much with U2 yet, all i Know for sure is that it def hits blanka out of his Ball. I’m sure most of these work for U2 also, but feel free to let me know and I’ll update the list ofr U2 and Ex moves/Ultras