I have the Waterfi Shuffle, it worked great for about 9 months, then the battery started to die between swims.
The buttons on the device are definitely "stiff" as the instructions state, but they still work. I can adjust the volume, skip, etc right while I'm swimming.
The earbuds that came with it included several different sized rubber thingies. What I noticed is that getting a good seal is important, since once a bit of water gets in there, and covers the transducer, the sounds dies. I found the right size, but also had to shove them in pretty deep. This is however a very personal, individual fit kind of thing, so you may be fine with the stock earbuds. I replaced the earbuds with a different set that have been working better, after the wire got damaged, and they were out of warranty.
The battery issue seems to be something inside the device, since it runs fine once it's fully charged. It just doesn't hold a charge overnight, so I would have to plug it in every night before swimming. I used to get a couple weeks out of it before, swimming 2 - 3 times/week.
It has a two year warranty, and after emailing them, they gave me instructions on sending it back for repair/replacement. Just sent it out last week, so we'll see how that goes.
I use mine on shuffle, and have also done playlists. I just don't use iTunes that much but 2 GB seems to be enough to get me through swims. So much so that I can't go back now, must have music to swim!
While I have nothing to compare this to, I would still recommend it, especially over a waterproof case.
Edited by tcj103 2014-05-12 12:59 PM