haven't used these too much to justify a response, but I have used aguf,
has coloration of hp bar per spell i.e. yellow disease, blue magic
coloration of hp or name by class
texture and look configuration
all the frames are in one folder vs separate frames for separate folders i.e. ouf player frame, ouf party frame etc.
Probably missing some stuff, but those are the things I can think of, regardless I'm considering waiting on Haste(sp) to release the newer ones, before I go back to using these, I really enjoyed the font resizing in game, and just the clean look. Wouldn't mind Ouf all in one folder like Aguf is, if that's a future plan...flip flopping between aguf and insomniax, easy fonts to read is great :>