I have a pair of Force Fins, for when I dive in colder water. There great very low Kick effort. There not the fastest fin in the world, but have more than enough power entering a zodiak. I would highly recommend the optional bungees as it makes donning/removal a snap. The main reason I like them, is that I find I have so much more energy at the end of a dive, & if I have to put the power on I can maintain it for much longer.
I am Currently going through Dive Master Class through PADI, & part of the qualification to pass is you have to do a 800 Yard swim in roughly 17min to pass & roughly 12min to get a 5 which is like an A. Wearing mask, fins, & snorkel, only using your legs & head in the face down. Right now I can do it in 13min wearing my force fins, & am working towards the 12min 30 second mark. With my Oceanic V-Drive fins out of the gate my time looks really good but as I go on, my pace slows so that I end up at about the same time, & my muscles are killing me especially my ankles & calves. So at the end where my force fins I felt like I got a good workout, with my V-Drives I feel like I pushed myself to the limit.