Personally my own $0.02, and this isn't a "fin test" so much as my own feelings from swimming the fins. I've found fins are like shoes, there's no one fin that does everything well, everything is a compromise. Just like there are different optimal shoes for hiking and running. In my collection, I have many fins including:
SC Seawing S-Tek
SC Seawing Supernovas
SC GoSport Gorillas (never tried the regular GoSport or GoTravel)
Mares Quattro Avanti
SC Twin Jet (split fins)
My diving generally falls into 2 types: 1) recreational single tank diving on a reef looking at wildlife; 2) technical doubles diving on/inside a wreck. All warm water in rashguard or thin wetsuit. I dived the first three pairs over the last year. The last two pairs are retired. I also have one knee with a torn ACL.
I like the SC modular system. I can bring both S-Tek and Supernova blades traveling and with 3 divers in the family all using the same system, we can swap blades.
Supernovas are really excellent for flutter and modified flutter. Excellent acceleration and cruising speed and low leg stress. Frog is good, but not as good as the S-Tek or GoSport Gorillas. The blades are very flexible in one direction so that's it's strength and weakness. Helicopter is mid. Back kicks are meh, it feels like they are flexing too much. These are the fins I want for long surface swims and cruising around in open water. Flutter kicking in doubles is fine. I don't want these fins deep in a tight spot inside a wreck where I might have to back out of a hole or avoid turn in place to avoid silt out. The performance reminds me of split fins (excellent for flutter kicking) but without the excessive floppiness that makes split fins poor at holding still or minute movement. I like the Supernovas for recreational diving and snorkeling. I even like them for tech diving if I don't have to do a lot of helicopter and back kicking.
S-Tek took the Supernovas and removed the hinge for a stiff pre-angled blade (30 deg). Removeable plates can change the buoyancy from positive, neutral, negative. They are not as negative as Jetfins, just slightly negative. The stiffness improved frog, helicopter and back kicking over the Supernovas. But the non-hinged blade made it a bit more work to flutter kick. Interestingly my wife when diving the S-Teks subjectively liked them more than the Supernovas because she believed she could go faster flutter kicking in the S-Teks. I think she was wrong, because I could not keep pace with her on the reef when she was diving the Supernovas and I was in the S-Teks, but when we swapped I could effortlessly swim circles around her. I think she was feeling the S-Teks require more muscle effort to flutter and so she felt like she was swimming faster - even though it was probably illusory. I like the S-Teks for tech wreck diving because they are a good all round fin for alternate and flutter kicks. For any diving with a lot of flutter kicking, they would tire my legs a bit more compared to the Supernovas.
GoSport Gorillas are compact and good for travel. Also good for tight spots like penetrating a wreck. They are stiffer than the regular GoSport, probably similar stiffness as the S-Teks. The pre-angled blade (~20 deg?) is less than the S-Tek. They are good for frog, helicopter and back kicking because they are stiff and relatively flat. I can't tell how they compare S-Teks for alternate kicks because I never A-B tested them. But they are definitely better than Supernovas for alternate kicks. For flutter kicking they can be a bit stiff and harder on my legs. These are not great fins for long surface swims or snorkeling. They are worse than the S-Teks for long extended periods of flutter kicking. Don't know if it's because they are shorter, the blade angle, or lack cut outs or something else. I've used these for tech diving inside a wreck where shorter length and maneuvering is important and I'm mostly alternate kicking. I got these before I got the S-Teks, so in the end I might not need both. As I mentioned I like the S-Teks better for flutter, but I am unsure how the alternate kicks compare between the two.
Mares Quattro Avanti are my oldest fins. For perspective, they're good to OK, but not excellent at any one thing. Jack of all trades and master of none. They do everything OK. Compared to the others they are a bit long for a suitcase. Long extended flutter kicking is OK, but can be tiring. Alternate kicks are OK, but a touch floppy.
