I got one of these for Christmas a while back; I was quite happy with it at the time, since I had no previous experience with graphics tablets and no expectations whatsoever. After a couple of months I noticed that the tablet was losing track of my pen movements more often (it had done this from the start, but not so much). Changing nibs and batteries made no change.
Nowadays if I were to draw a straight line across the tablet, it would either not register at all, or register as a series of haphazard dashes. It's absolutely useless as a drawing implement. The entire premise of a tablet is to give a natural flow to your lines, but this is less natural than using a mouse with your foot.