Yes, there's been plenty of discussion here and elsewhere about what the fastest fin is. Interesting, therefore, that the type of fin preferred by those who compete in finswimming races is a monofin, which nobody has yet suggested.
I'm very wary of "scientific tests" to determine the "best" fin. Not because I'm against scientific experimentation, far from it, but because the testers would have a really hard job controlling all the variables, and if you can't control all the variables, you won't get a credible result and people will be sceptical about whatever hypotheses you are trying to prove.
From my viewpoint, fins are worn for extra power, manoeuvrability or endurance, or a combination of the three. In my fifty years' experience as a snorkeller, very few fins satisfy all three criteria, which have a degree of subjectivity and undefinability about them anyway.
What's needed in fins is the ability of said fins to sit comfortably on your feet and to match your swimming style. This is a highly personal problem-solving process and it can't be rushed by following other people's recommendations about brands and models. Finding the perfect pair whose foot pockets fit your feet precisely - not just lengthwise, but widthwise and heightwise too, is something of an odyssey in itself, even before you begin selecting fins for blade stiffness.
For what it's worth, I prefer snorkelling with old-fashioned rubber full-foot fins. They suited me perfectly when I started snorkelling half a century ago and they still suit me perfectly now. Contrary to popular belief, I wear my full-foots with booties, never barefoot, and they still fit. Would I recommend them to you or to anybody else? No, because I'm me and you're you. Your priorities, physique, swimming style etc are likely to be different. We live in a diverse world and the world is better for it. Dare to be different!
Do try a variety of fins before you select a pair. Resist any sales pitch pushing you in the direction of one manufacturer or even one fin type. Just because a majority of people around you have opted for one brand and kind of fins doesn't mean that they are also right for you. You wouldn't let anybody else pick out your clothing for you, so try out several different designs and only settle on your purchase when you're happy, even if your choice makes somebody else unhappy because you've haven't made the same choice as them.