I've been considering this tool for some time.  I'm so glad to have it as part of my new swim training / fitness routine.  Having a bad back, the monofin makes one move differently but such that it stretches and flexes the vertebrae as to improve my posture in just 2 weeks.  In combination with a new routine the use of the monofin rounds out or rather balances the swimming workout.  It seems well made and is certainly designed well.  My only reservation and the reason I can't give it all 5 stars is that there is evidence of premature wear in just 2 weeks, so I must early on question the durability of the monfin.  Other fins I use for either training or scuba diving have not shown this early indication of wear.  I enjoy the monofin very much and is an important part of my daily training.  I'll just have to wait and see how well it wears.

Looks like a quality product, however, I didn't get it out of the house!  I tried it on at home in the living room, and the foot pocket was way, way too small and narrow for my size 10E foot.  I expected to have room for some neoprene socks, being that the fin is suppose to fit size 13 feet, room enough for my feet to swim in (PI).  I will be returning this product, as soon as I find my paperwork.

I replaced a smaller fin with this one and the results are great! I swim primarily in a lake, will have to wait until I can report on ocean swimming. This fin is fabulous! The straps tighten with a ratcheting mechanism and don't slip off your heels or loosen while swimming and the strap has a stop on the end so it won't come completely out. The quick release on the sides is handy and easy to use. And it floats... it'll stay just below the surface, but you won't lose it to the depths should it get away from you. An WOW! Does this thing move you through the water! I LOVE IT! No cons, all pros. Highly recommended.

I love the Monofin.  It's fun to swim this way and I use if for snorkeling here in San Diego.

However, I do have a few issues.  
1) The foot straps kept falling off my feet.  If you take it really easy you can still move well, but if you accidentally kick too hard they slip right off.

2)The strap broke the first day.  Also, since it's non-standard strap I couldn't get a replacement at the local dive shop.  As a mater of fact, I can't even find a replacement here on www.SwimOutlet.com .  The closest I could find was the "Finis Replacement Wave/Tempo Monofin Straps"

I've jerry-rigged replacement straps on my own but even those keep falling off my feet.  Working on it.

FYI I haven't even contacted swimoutlet.com about this (does this review count?) so I'm not blaming them or anything.

very strong and sturdy, i like this product alot, and would recommend it to anyone looking for a monofin!

I bought this to have fun and work on my dolphin kick/butterfly stroke. This fin amplifies the power of your dolphin kick and in doing so helps train your body to do the dolphin more effectively sans monofin; I have definitely improved. I did find the material to be a bit stiff, but perhaps it will soften over time. You can also buy some sort of monofin aqua socks to minimize strain/friction on your feet, but I have yet to experience these special socks.

You can gain some impressive momentum with this item (my goal is to swim with dolphins), but given the amount of water you are moving with each kick, there is significantly more pressure on your legs and I have cramped given the additional strain - I imagine this will wain with  more training.

Overall, I am very pleased with this purchase - lotso fun.