I recently bought an android based tablet. part of my intended use was for displaying sheet music at the keyboard.

but I would never use it as a backing track device because of the low quality soundcard. But then again, I wouldn't use a macbook or laptop for that reason either unless I had a firewire or USB soundcard connected to it. AFAIK, however, there are no drivers yet available for USB soundcards for tablets.

IF the drivers become available (and I don't know why they wouldn't eventually) for my MOTU for example, I would certainly consider using the tablet for an output for backing tracks.

but as long as I'm stuck with the onboard sound of the tablet, no deal for me.