I now have 8 dives / 10 hours, 41 min with the SCUBAPRO S-Tek Fins (size XL). This has all been on an Optima BMCL CCR in cave/cavern environments.
Prior to the S-Tek I used Mares Avanti Quattro+ (size XL). I have both weight plates in the S-Tek which make the fins about .2 pounds negative in fresh water (.1 pound negative each). The Quattro+ finds are neutrally buoyant in fresh water.
On the very first dive it took me about 30 minutes to fully adjust to the different feel of the fins. For frog kicks, I think the fins are about the same. I think the Quattro+ are better at the modified flutter kick, where the S-Tek is much better at reverse/back kicks and helicopter turns. I actually surprised myself the first time I did a back kick and saw how much I moved. Rhys Couzyn says these fins are great at the standard flutter kick, but that is not a kick I use very often and have not performed that kick style while diving these fins to date. I will use these fins when diving sidemount also, another style of diving where I used the Avanti Quattro+ fins.
I honestly do not see these replacing my Scubapro Jet or Hollis F1 fins. Even with both weight plates, they are still very light fins. In-water weight of the Hollis F1 and Jet are 1.2 pounds negative (.6 pounds negative each)...that is a full pound more negative than the S-Tek Fins. In back mount doubles with 2 to 4 deco / stage cylinders, I like the heavier fins.
With only one weight plate, the S-Tek Fins will float in fresh water with just the top of the bungee strap breaking the surface...I estimate about .4 pounds positive. With both weight plates removed, these fins float at the surface and are about .5 pounds positive in fresh water. The weight plates are about 2.75 ounces each.
My original idea was to have a set of finds where I could adjust weighting so one set of fins could replace both the Jet Fins and the Quattro+ fins. That simply can't happen because the S-Tek Fins are too bouyant. They can be adjusted from slightly negative, to slightly buoyant, to very bouyant. I also don't think it is smart to be changing the plates very often...they screw into a piece of plastic and after a few times removing the plates, I already find that the "bite" of the screw is not what it originally was. I can see these stripping if changed too often and requiring a new plastic mounting plate to screw into.
I have not played with the MFS, but I will be heading to the Philippines in January and will separate the foot pocket and blade for travel. Scubapro provides 4 lock plates with the tool they ship with the fins, and I see they are now selling 4 lock plates on their own. Are people losing their lock plates left and right...or, like the weight plate screws, do the lock plates weaken after multiple uses and will no longer securely lock into place?
For me the S-Tek Fins are an excellent replacement to the Mares Avanti Quattro+ fins. Since they lack sufficient negative buoyancy, they will not replace the SCUBAPRO Jet Fins for the Hollis F1 "Bat" Fins. I also feel that you need to find the ideal weight you want for the fin set and leave it. The design of the weight plate retainer does not lead itself to being something you want to be removing on a frequent basis.
