Got one of these for a new small laptop. It was a struggle getting the USB bit in but I liked the feel of the mouse when setting up the machine. Then I went to put it away until Xmas and simply could not get the USB bit out of the laptop. I'm reluctant to use pliers in case I damage the laptop. Meanwhile a friend had got one on my recommendation and couldn't get the USB receiver in at all. In the end amazon gave her a refund. When I looked at her USB thinggy I found that it was totally non standard - compared with other USB plugs that work fine (external drives, memory pens etc) the slot to receive the tab from the USB socket on the laptop is far narrower. Most seem to be around 50/50 but this mouse has more like 60/40. So one to avoid until they fix this elementary error.
Update Jan 2011: I upped it from one to three stars because since I managed to get it out from the USB socket and spent a while working on the USB receiver with pliers and a nail file it's actually worked very well - I can remove it with a bit of a tug and it's still on the original battery. It doesn't mind if the little USB receiver is the other side of the little laptop, is comfortable and seems to work on a variety of surfaces, desk, paper, arm of a leather sofa etc.