don't buy into anything the Apollo guy just said, it has been shown too many times that Bio-fin do not create lift. The simply push water out of the way like paddle fin. In order to create lift you must create a differential pressure on opposite sides of the blade, and the giant split down the middle prevents that from ever occurring even if it was actually designed to, and if it did actually create lift the lift force would be perpendicular to the lifting body, if you actually look at the Bio-fin and other splits, that would be a lateral force that is being canceled out by each side of the blade, not longitudinal that can actually push you forward. This is why you have to wear a fin strap on them, and why people use spring straps because they are under so much stress they break. While the Bio-fin is actually a very good fin, certainly in the top 5 for recreational divers, they work simply by channeling the water in a generally rearward direction, which is a huge step up from most paddles that 90% of the water slips off each side.
As for helping to pick a new fin for you, JeffToorish hit on the real points, what characteristics do YOU have, and then hopefully we can provide useful input as to what might work well for you. For example, if you are used to splits, suddenly swapping to a Jet, as most of the post have recommended is simply stupid, none of those people have bothered to even ask the appropriate questions to identify what YOU are looking for, so their "opinions" are their own and are not really recommendations for YOU as a diver.