... that the NWZ-A847 I bought in February 2011 has a function (AVLS) for switching Volume Limit to On or Off, and volume is more than adequate. The clarity of picture and sound, and the Noice Cancellation function (especially when travelling by train) are awesome. And I managed to view i-Player programmes after first downloading them to my PC using the PDA setting. All the other good stuff has been covered amply already by many others.
This player does have a good sound but it is not much better then an ipod 4 touch . The best thing about it is , however is that you can use drag and drop and Windows Media . I have other Sony MP 3 players S639F and x1060 and they are both of a higher level in sound and quality. You will have to adjust the volume 3 notches higher to match it . To be truthful I was a bit disappointed in the player as a whole but it is a nice size and brilliant clear display.