One difference is which jets and which IDIs are being compared. In the last year, due to changing drysuits and swapping fins with a buddy, I have had turtles, XL jets and power fins. The large jets are similar to the powerfins. The XL jet is about an inch longer and an inch wider than the powerfin. The turtle blade is quite a bit larger than the other two. A buddy and I swapped my powerfins for his XL jets a bit ago. The pocket on the powerfin is a bit bigger that XL jet pocket. He needed one slightly bigger and I needed one slightly smaller. It may be because the powerfin is a bit shorter, but I felt that it was a stiffer fin than the XL jet. I much prefer the jet. And actually, I preferred the turtle of the three but I don't have boots large enough for them anymore. If you have the legs to move them, the turtles will really move a body along.
JoelW
JoelW
