pro 2004 Edition:
-for whatever you might say about Lucas' irrational devotion to SFX and image quality, you have to admit, they look pretty amazing (clarity, color accuracy, etc.)
-better Jabba (why they couldn't get him to the quality of his PM counterpart I can't figure ...) and other CG characters
-Ian McDiarmid in ESB
-Updated ROTJ ending celebrations
-Han is getting closer to shooting first again LOL
things I didn't care for:
-Anakin's ghost - that's fairly unforgivable IMHO
-green lightsaber in ANH? How did this happen? and lightsaber inconsistencies in other scenes ...
Other than that, the changes seemed pretty minor. Honestly, I don't see how refusing to release the O-OT gets Lucas more money. I think it's a case of an "artist" being too interested in pleasing himself to accept outside input. That can be seen as a good or bad thing ... personally, I wish I could have a nice transfer of the films as they originally were. LOL, but somehow, I don't think that's an original thought on these boards.