I have the original Fusion from Whites, which has the same dry core but a more simple spandex outer shell compared to the scubapro Fusion ( Whites manufactures them OEM for Scubapro)
I'm not sure about the buoyancy of the SP's outer shell, but my fusion dives with the exact same weight as a 5mm wetsuit. I am drysuit certified, but my cert was some 10yrs ago. When I bought the Fusion this spring, I was worried that my training may fail me since I've been out of touch with a drysuit for so long. In spite of my worries, it dove and felt like a wetsuit. I did try some tricks like hovering head down etc, but didn't have any air bubble control issues. (Pls note I was diving in tropical conditions with Whites MK0 undies. They're just spandex coveralls with zippers in front and relief, adding near-zero buoyancy)
I don't know what the Ever Dry 4 is like, so I won't comment on that, but I sure do love my Fusion. If you browse through the threads, or use the search function and look for opinions, you'll find lots of divers on this board who own and like the Fusion.
Hope this helps.
Kaza
