jets vs Garas
Thanks to all for the info, real good thread, but I am more than a little mystified, some of this does not match my experiance.
I switched from standard jet fins to an early model of Gara 2000hfs about 22 years ago, now wear 2000hf"s which are supposed to be a relatively stiff freediving fin. I used both types for scuba and freediving, 1000s of hours of both. This is my experiance.
The jet fins are short, stiff and great for manuverabilty and good on short acceleration, like going after a fish you just speared. Also good for body surfing if you have very strong legs (which I don't). They are great for doing surface dives, much better than Gara's. After 5 or so hours in the water, sometimes my legs would get crampy, but not much.
The Gara's (relative to the jets) are long, very flexible, and not very manuverable above or below the surface, slow on surface dives and terrible on acceleration, but once you get moving there is nothing like them. I could not tell much difference in max effort top speed, but for steady effort, the Gara's are vastly more efficient and faster. They considerably extend your depth range freediving. I think they are a little easier on my legs than the jets. Overall, they are far superior to jets for scuba or freediving and , I suspect, superior to any other "scuba" type fin. Split fins I don't know anything about.
This all seems quite different from some other posts. I sure would like to know why the difference.