Some may be sceptical about using such a device as a mouse for a PC, but as I suffer from wrist RSI, this has been a God-send.
The mouse is fully customisable via the Logitech application software, and whilst it takes a few days to get used to, I have no problem using it with applications such as Photoshop.
It really does take the pressure off you moving the mouse around all the time, but the only down side is that it is not the best thing to port around - if you have a laptop, squeezing into your bag may prove slightly tricky....
Overall, a worthwhile purchase, and I do hope that Logitech still manufacture this item for the foreseeable future - such items are becoming increasingly difficult to source and find in store and over the interweb these days.