Very comfortable, light.  Cut my time dramatically.  Much more comfortable than other fins I've used.

These are so light and comfy.  My old fins were really rubbing my feet - had a flashback to the old days of trying to get sweat socks on while hanging on to a lane line.  These took to my feet within a 50, and I didn't even readjust once.  They are a little funky to kick with at first, and feet placement on flipturns had to be figured out.  However, at the end of the first workout, I could feel it in my calves but not my feet.  These are definitely worth a try if you have sensitive/difficult feet.

I ordered an xx-Small. I wear a women's size 6 1/2 shoe. The style of these allows for equal down an upbeat in your kick. Unlike Zoomers, these do not put added strain on your ankles, knees & hips. As a swim coach, I recommend these to all my swimmers.

I use my fins alot in my workout--both for swim sets and kicking sets.
They are light weight and give my ankles a stretch.  The light weight helps me kick faster than I do with other fins I have used.

I use these for "Fun Fin Friday" with my workout buddy.  I own a pair of "normal" fins and was surprised at how much I had to work at keeping my feet underwater with these!  They are a good workout, just different from the regular fins.

I haven't worn these very much yet. They fit pretty tightly, though my shoe size is right at the top of the recommended range for the size I got, and they don't feel like they're in any danger of slipping off while I use them. These feel much more like an extension of my foot than my old heavy zoomers. I have pretty good rotation anyway, so I don't know that these are magically improving that, but they're certainly not getting in the way of my rotation. Because of the design, I sometimes feel some pressure from the blade right over my big toe when I kick down, but it doesn't seem like it's going to buckle. The biggest area where I've noticed a change is in how light my swim bag has become from carrying these versus other fins. These are basically made out of the same material as Crocs.