I've always used Aquaman so can't comment on others. Best 3.8 training swin in a 50m pool 1:12. Best swim in an Ironman in a suit 1:02. I no doubt benefited a little from drafting in the race but most of the difference was down to the suit.
I reckon open water swimming in a suit on my own is safer than mountain biking or ski-mountaineering alone. Do a bit of research about currents before you head out and there's not much that can go wrong apart from being run over by a jet ski.
