Welcome to the forum.
I doubt you'll find any really good RAW photo editing apps. The iPad just doesn't have the power to do this well. But if I'm wrong and you find something good, please tell us. I wouldn't mind having something along that line myself.
I don't use my iPad for photo review, but if I did I'd probably shoot RAW+jpg. The jpg would be enough to let me know if I captured what I wanted, or close enough. I'm kind of addicted to the 27" screen of my iMac for actual editing.
And before you get the wrong idea, I'm just an amateur, and not a particularly dedicated one.