For Ibuki and Xiaoyu, I've got them in English. I felt Kat Steel did a much better job as Ibuki in Super Street Fighter 4, so I might change her soon. As for Xiaoyu, I actually love her English voice. The only problem I have with it is during her Hakkeshou Combo cinematic. There's this one part near the end where she just makes a really horrible sounding grunt. I can't believe they actually thought that was okay. On the other hand, both Ibuki and Xiaoyu's Japanese voices are actually better than they were in past games to my surprise, so I'll probably switch to them pretty soon.
Overall, most of my cast is in English, except for the following:
Street Fighter:
Akuma (Akuma's English voice doesn't seem to be getting any better.)
Juri (The English voice actor has improved, but the Japanese one is what I'm used to.)
Ryu (Kyle Herbert is fine but the Japanese one just fits like a glove.)
Tekken:
Hwoarang: (Can't stand his English voice.)
Jin: (As cool as it is having Light from Death Note as the English VA, he unfortunately failed to deliver as Devil Jin.)
Julia: (Sounds nicer to me than the English one.)
Kazuya: (Kazuya's English voice...not feeling it.)
Lili: (I switch back and forth. I like both voices.)
Nina: (An odd choice, I know. Nothing wrong with the English one, but I do like how the Japanese voice sounds on her.)