I've been diving the Hollis F-1's for a couple years now. I was actually one of the testers for these fins and the ones I have are a set of the prototypes. They are an awesome fin! And now with the new two color ones coming out (not sure of the release date) they are even cooler! And yes I have a set of the prototypes of those. The only reason I was keeping my Blades was because my original F-1's were XL's and were a little sloppy with my thinner boots. The new two color ones are the next size down and Goldilocks would say they are just right for my thinner boots and the drysuit. And they are easy as hell to see in low vis. Had them on checkouts two weeks ago and they really do standout. You cannot miss those tips moving through the water. They have the same 3 position spring strap adjustment system and like the orignals are slightly negative in freshwater so they should be just about neutral in salt. They were designed that way. There were a couple of the orignals that had an issue with the pocket tearing that I know of from posts on here. Hollis was very quick to take care of that from my understanding and I'm betting that like any molded product there were a couple that might have slipped past quality for whatever reason. Make a few thousand of a new fin and it is just odds that a couple will have issues. I also understand that the production run of the new finsa will have a little smaller area on the tips that is the new yellow color. Not that it makes a big difference. Mine are quite wide and a little uneven but they are prototypes and I don;t give a rats ass about an uneven line on a fin. If someone does they are too much of a prissy wuss for me to dive with anyway. Again I can't think of any reason for me to dive any other fin. I refuse to pay 200 or even 150 for a fin. Even if I could I'm not that loose with my money. The Hollis fins are my fins from now on.