Jupiter, Cozumel & Belize are quite different.
Here's my 2014 Jupiter Trip Report from the Goliath Grouper aggregation. A few points:
1.) The week I did 10 dives there, the viz. in Jupiter was much less than in Cozumel or Belize, but adequate.
2.) With Jupiter think sort of a ledge edge of a fairly flat plateau underwater, with a 'lawn' of reef on it, rather than what many people think of a 'reef' (e.g.: sloping or vertical wall, or the spur & groove formation).
3.) Jupiter is sought out for big animals, particularly the lemon shark migration early in the year, and the Goliath grouper aggregation in the Fall. It's also a place where people go for shark feeding dives.
4.) Jupiter & Cozumel are drift diving. Of my 10 dives at J. & 2 at Cozumel, they were both 'hot drop' where the boat follows for later pick up. The Belize live-aboard moored and we came back to where the dive started.
Appreciate a place for its own merits or you may well be disappointed. If you hit Jupiter expecting the great viz. & varied topography Cozumel is famous for, you may be bitterly disappointed. But if you come the right time of year looking to photograph numbers of Goliath grouper, for instance, you may love it.
Richard.