Personally, while the general view from CG is nice, the view of Wishes is nothing special. Most of the fireworks are shot way out in the distance, so you don't really get that "magic" feeling like you do when you are standing on MSUSA. And, if it is a little windy that night, it could make viewing outside a little uncomfy, IMO. The view of Wishes from CG only adds to the over-hype I think the restaurant gets, but doesn't deserve.
Personally, there is no view of Wishes like the view from MSUSA. I would much rather, depending on what time Wishes is the night you are looking at, either watch Wishes from MSUSA and then head over to CG for a late ADR after Wishes (which will give you a much quieter, romantic meal since the crowd tends to thin out after Wishes) or eat before Wishes and then head over to MK for the show.