The full foot fin is usually much cheaper to buy. Moreover, as benha said, the FF fins do not carry the unreliable and drag inducing hardware. As a result, the FF fin is safer; most are also faster with more thrust than OH fins and swimming on the surface is usually easier and more efficient but not always due to something called offset angle or blade angle. They are lighter and easier to pack. Many FF fins use the latest technology to better advantage without being stiff, heavy or clumsy. The FF fins clocked the fastest slalom times beating the highest performance OH fins, namely Biofin and Smoke. Scuba divers like OH fins for various reasons, their buddies use them, they are "technical" and stuff like that. But mainly, they like the adjustable feature although most divers probably only use one adjustment anyway, but when a giant foot pocket is needed the OH is the way to go. Many of the newer OH fins have rather short, wide pockets making them uncomfortable with some male divers. Also, it seems to impair performance. On the other hand, some of the OH's are too big for some women. As to fit, this is the crucial aspect of FF fins. The fins must fit snugly when the diver is wearing the preferred boot or sock. Once the right combination is selected it cannot be changed unless both are changed. I suggest you investigate several types and consider the options and arguments. If you decide on a FF fin look closely at the Mares Superchannel, the Caribe X, and Oceanic V-6. If you like the OH type, the Tusa Zoom, the Aeris Mako, Atomic Smoke and the Apollo Biofin are well regarded. The OH fin pushed heavily by shops is the Tusa Imprex.
