On my wife's recent trip to Seattle to visit a friend she stopped by the Microsoft company store for a little geek shopping. One of the gadgets she brought home was a Microsoft Touch Mouse.
The mouse has a very solid feel and appears to be of quality construction. It has a good feel when moving around and clicking. The few available gestures are easy to learn and use. The gestures include: scroll, page back/forward, maximize/restore/minimize window, snap window left/right and show desktop/instant viewer. Overall the gestures work well and are smooth but I do have instances where back and forward do not respond. The thumb gesture required is a bit skewed to get use to. If you are left handed you can swap the thumb gestures to the other side of the mouse.
Cons:
1. Only works on Windows 7 so if you have a Mac or Windows XP, don't bother.
2. It is NOT a gaming mouse. Since the mouse has effectively 1 button where left and right clicks are based on finger position this creates problems for games like World of Warcraft where you frequently use both mouse buttons at the same time.
3. Very limited customizations. You may not change the behavior of the gestures although there isn't much flexibility on the Mac either.
Pros:
1. Build quality. This is a quality and solid feeling mouse.
2. More functionality with less buttons.
3. Low profile dongle for laptop users.
4. USB extension cable for desktop users (to keep the receiver in range)
5. Storage compartment for USB dongle.
6. Uses AA batteries so replacements are easy to find.
Overall I would say this is a good mouse and worth the price if you want gesture based control in windows 7. However if you don't care about gesture based control then stick with your existing mouse.