As far as the s9 cutting out, it definitely will cut out if you place it in your pocket. It is a weaker device, but this is what gives it such a light weight(i think it is the lightest bluetooth stereo).

The problem I found was that coreplayer has horrible sound quality when compared to WMP. I thought I had grabbed a bad mp3 when i first used coreplay...then i played the same song in WMP and it sounded much better.

If you do buy Motorola S9 headphones...make sure you buy them somewhere you can return them. They can be VERY awkward...they stay in your ear, but they have a tendency to "pinch".