I'm a big fan of the frog kick.
Of course, for cave or wreck diving, no other possibility beats the modified frog. Add to that the fact that I tend to do most of my diving in a silty-bottomed lake (Lake Travis near Austin, TX), where a modified frog is ideal for staying close to the bottom without kicking up a siltstorm.
I've also found that my breathing tends to be more relaxed and my calves are far less likely to cramp. For underwater mapping and navigation, the frog kick is ideal because I tend to frog kick in a straight line, regaredless of the visibility--not so with a flutter kick.
I dove with Mares Quattros (great fins) for a year and a half but switched to Atomic splits. Both fins work equally well in the frog kick, but in a pinch (like, say, against a current or rushing to catch a student who doesn't know he's heading toward the surface), the split fins are far more efficient that the Quattros.
For both the Quattros and the split fins, I found that I had to modify my frog kick slightly so that the edges of the fins move out in more of an arc than you would use with rocket or turtle fins. Once you get this maneuver down, though, you can out swim the DIR guys--even going backwards.