I was sceptical that this would work but figured at the price I could afford to make mistakes. It is smaller than you would believe. My laptop has recessed USB ports and in effect this thing just disappears! If the sides of your machine are flush with your USB ports then it might stick out 2-3mm.
I am running Windows 7 Professional and it pretty much installed all the drivers itself - I have been using it for about 2-3 weeks and I have been travelling with it stuck into my laptop during that time - no problem with it snagging as the laptop slides in and out of my briefcase.
It has worked with all my bluetooth kit - and the connection has been more reliable with my bluetooth mouse than the inbuilt bluetooth link in my previous laptop. I wouldn't give this widget up for anything!
Buy it, plug it in, forget about it :-)
Andy