Recently traded in my Treo 650 for the XV 6800 and must say, so far anyway, rather unimpressed. Using the phone to play MP3's, I find the sound quality is rather 'tinny', and the volume is weak. I am using WM10, provided with the phone (running the upgraded 6.1), and have also downloaded a trial version of "Kinoma Player".

Kinoma provides an excellent interface, but without the paid version, you have no control of bass/treble, which when activated should improve sound quality.

But volume is surprizingly weak. Cranking up the Treo to 100% will blow your eardrums out the back of your head. The XV6800 doesn't come close. And the speaker of the Treo is clear and loud, the XV again is tinny, sounds like a cheap am radio....

I'm curious: have you found a good fix for music? Perhaps a good pair of BT headphones with their own volume control?