I have almost exclusively been diving the Volo Race (full foot version) - they are amazing in my mind. I have never had any issues catching up with people in currents, and find that they work well for all kinds of kicking, I mainly do frog'ish (I turn my feet so one sole is pointing in and one out), and then I do dolphin kicks if I have to go fast and have the space for it. If you're used to big rubber fins you might have to alter your back kick though since the side isn't as tall. At surface swims I'm always faster than most other divers despite going relatively relaxed. Due to their length and flexibility I also find that you can get quite a bit of thrust from small ankle movements for swimthroughs and the like. While providing this power they are also some of the least straining fins in terms of your ankles I've tried, you get a lot of movement compared to the energy you spend. They feel so natural to wear that everything else I've tried so far just feels wrong - either it feels big, clunky, and straining (e.g. Avanti) or like not moving anywhere (most standard plastic fins).
I haven't tried them with heavier equipment than standard tropical diving though, I would suspect that they are less efficient if hauling steel tanks and the weights needed for drysuits - but can't say.
Oh and they've lasted 10+ years of diving and snorkeling now, typically being strapped to the outside of a backpack that's being thrown around (the two holes are great for tying them down), and are only just starting to crumble a bit in the rubber parts, nothing too serious though - still going strong.
