I haven't tried anything other than the x1 so far. I'll try my old sansa and see if it works. I'm a bit skeptical about the cable so that will also answer that one.  

Thanks for the reply. You're probably right about the bluetooth thing but the first time I had it connected and working, I also had the phone with me in the car and bluetooth was on. Thinking about it again, I might have only had the phone paired to my suunto which would explain why it worked...

I bought one of these a week or so ago. I was excited to be able to play music in the car without having to deal with cd's all over the place. I've not really been able to use it enough to say if I like it or not. As far as the unit itself goes, I quite like it but he wheel control is way too...