I'm just beginning to shoot with my new X10. The JPEG image quality is superb, and once Lightroom updates to allow for RAW import I might happily travel with this as my main camera. (But I doubt if I would ever leave my X100 behind).
Incorporating the power switch in the zoom ring might seem like a good idea, but it has a downside: any time I want to review images I need to extend the lens and take off the lens cap. This is frustrating. But I guess I'll get used to it.