If you are a frequent Windows 7 user, i would recommend this mouse. If you have Windows 7, but only use it occasionaly, you would probably be better off getting a cheaper mouse. I bought this mouse from amazon, and it arrived 3 days later... at first it didn't work, so i sent it back for a replacement as i thought there was something wrong with the mouse itself. Turns out you need to download some software to get it working with your computer.
Go to the microsoft hardware website, find the touch mouse and under 'support' tab, download the software and drivers file.
The mouse is a good weight, because when you do one of the sweeping gestures, you don't accidently drag it across the desk. If you've ever used an Apple touch mouse, you'll have an idea of what to expect, except for a textured plastic finish instead.
I've given it 4 stars because the scrolling isn't that fluid - a bit like the scrolling on a traditional mouse - but perhaps that'll just take some getting used to.
The best feature is the three-finger gesture, to quickly see all the windows you currently have open. It also has BlueTrack technology, which means you can use it on any surface, perhaps if you're away from your desk, say, on the roof?
I would recommend buying this directly from amazon, because if you really can't use it you could always return it, for free.
Comment if you have any questions
____________________________________________________________________________________________________________________
UPDATE
Sent the mouse back because I didn't get used to the Right-Click and Scrolling: For right-clicking you have to press harder, for slighlty longer, and scrolling isn't fluent enough - you either scroll a tiny bit down the page, or you find yourself near the bottom of the page... Have bought a Microsoft Arc Mouse to replace it, for my laptop, I will update with my firt impressions of it.