As noted above, the Vipers are a very nice fin. However, when scaling up for use in cold water, i.e., with 5mm of rubber, they become deficient because the foot pocket doesn't widen or deepen (the length is fine) resulting in foot cramping. I prefer the V5 Orange Dot flex blade in warmer water using fin socks of 1mm or less - it cruises me out to the line-up well and I tend to use my arms for take-offs more than most prone riders (maybe because I started out as a standup rider before opting for the prone riding paipo board) so not havingt the stiff blade thrust isn't an issue for me. After trying out several different fin types for winter use, I settled on the Hydro Techs (not the Hydro Finz Original and the Tech 2). The Hydro Techs were too rigid, heavy and had too much blade; the Tech 2 fit very nicely but simply didn't move me through the water in the winter.
Swim fin preference ends up being a highly personal choice - we can all provides lots of personal preferences but in the end it will depend upon the size and shape of your foot, the torque of the blade on your ankles and legs when paddling, and your wave riding style.