The force fin is a no-brainer. I believe the main problem with those that dislike them is their inability to adjust to the lack of resistance. I will admit, it does take a while to get used to the feel, but once you reach that point, you'll never go back to a conventional fin.
Now, most sport divers are in the water for an hour at a time, more or less, just taking in the scenery, and most conventional fins will be 'OK' for the challenge of a strong current, but if you find yourself having to really kick for an extended amount of time, you're going to find that the force fins are by far, superior.
The stiff legged kick that most of us are used to is not required while using these fins. You can use a bicycle kick, frog or dolphin kick with a result of excellent forward thrust. Also, making quick turns or spins are much easier as well, as the force fin blades do not have the raised 'edge bracing' you find on almost all other fins. consequently, there is no lateral resistance from the blade while making turns.
I've found that just spreading your toes while kicking seems to contribute to the 'right method'. The first time I did this while kicking, I remember thinking to myself.." Now I know what these fins are all about!"
I know many commercial divers that swear by them. I, as well, feel that they are the best fins available. The navy seals use them, as do many special forces units around the world.
The materials used to mold force fins are top quality and are by no means cheap. This has much to do with their higher price, but it is the superior materials that contribute to the amazing durability they possess. I've had a pair for 15 years and they are as resilient and flexable as they were when I bought them and I've logged thousands of dives since then.
My main use for these fins has been while working as a 'golf ball retriever'. Some of you may think that's an easy job and no real challenge for a fin. Well, I can tell you, nothing could be farther from the truth. 'You' try swimming with 70 pounds of golf balls around your neck, while pulling a floating compressor through thick weeds for the length of a football field. Also, try it for five or six hours at a time....I used to do this on a regular basis and 'then' play with a showband that night, for another four hours. The force fin allowed me to do this 'without' leg cramps or muscle fatigue.
They pack easier than most other fins and are lighter than most other brands. Also, the optional bungie cord heel strap is a must have for those who have experienced the frustration of hasseling with clips and assorted weird release systems you find of other fins.
Another great bonus with these fins, is that I can drive a golf cart while wearing them do to the shorter blade length! I put them on once and leave them on all day, as walking forward in them is a breeze.
Their user support is about the best I've experienced anywhere. I found that Bob Evans, the company's founder and inovative designer, is very accessable to those who have any questions or problems. He's also a great guy just to talk with.
Please, do yourself a favor, fork out the extra cash and get yourself a pair, but use them on a number of dives to get used to them. I have no doubt that if you do, you'll become an avid, force fin fan!