They are sooo comfortable and light but... I go to H20 aerobics about twice a week, I've had them about a month or so and they are already loose and the the back bungie thing on one has already broke (that's not that big of a deal).  So if you're planning on excercising in a chlorine... may want to think twice.

Update on 12/11/12:  I still have them and they are still stretched out, however still functional.  I've used them in the pool probably 75-100 times now.  I would recommend the purchase.  Just don't be disappointed when it stretches or discolors a bit.  Some of the nylon is now a light grey.  Worth the money though.