@josh37: I'm with vladimir on this. What's wrong with your Scubapro Classic BC? If there are any parts on it that require repair, you'll probably be impressed with Scubapro's customer service. One of my buddies has owned a Scubapro Knighthawk for years (10+?). In that time, he's only had a few minor issues with the BC: a couple of plastic buckles busted once and the seam on one of his weight-integrated pockets started coming apart. On all three occasions, Scubapro fixed the issues at no charge.
There are a lot of great rear-inflate BCDs and BP/W rigs on the market for under $500.
Although I'm sure the Mares Icon would work out OK, it wouldn't be at the top of my list.
The best advice I could give you is to demo the BCD on a real world dive (if at all possible) before buying it.
Over the years, I've found that I prefer a BC with 2 tank cambands, a standard power inflater (easy to repair, inexpensive to replace), a simple webbing harness, one pull-dump/OPV, and the ability to take it apart for easy rinsing. For cold water diving, BP/W rigs which incorporate a stainless steel backplate are often easier to trim out and allow the diver to carry less ballast. That being said, with careful weight placement and some attention to adjustment/fitting, I could dive very comfortably in a jacket-style or conventional rear-inflate BCD, too. YMMV.