Super Street Fighter IV Arcade Edition was recently updated with playable Oni. If you haven't had a chance to get to an arcade to try out the character, or even if you have but you want to improve your game, visit the Super SFIV official blog, which now has a character strategy guide, complete with some of those sweet little damage hit boxes.
[end_p text="Continue reading for some screens" /]
I'll leave the translation to the pros.
There's a good chance that once Capcom's Captivate embargo ends in a little over twelve hours we'll get totally official confirmation that the home version of SFIV will be updated with Oni, so SF fans should definitely stay tuned in to their internet.