The overall features and usability of this phone are great. It's one of the great walkman phones that is brilliant when it decides to work.
However, my mum had one and it went faulty, turning itself off and freezing/reboot light coming on. It was sent off for repair and came back with a software upgrade, apparently fixed. It started doing it again but not turning off and the camera wouldn't come on etc so she got a replacement phone. That too went faulty.
In the meantime, my W580i had developed a common fault and it was replaced with a W910i. That developed the turning itself off fault less than 24 hours after me getting it and it wouldn't come back on again no matter what I tried. I went back to my W580i... the only fault that developed was the buttons cracking!