Yes, it is flat but that does not matter. Your entire hand does not rest on the mouse just you fingertips. I really like the action of the accelerated scrolling with the touch interface - it hardly takes any motion at all. Right click works perfectly as you would expect and the battery lasts forever. It is really nice to be able to get multi-touch on my older macs. I think there is a way to get it working with windows but I have not tried. I bring mine everywhere with me since I generally prefer a mouse to the touchpad (even on my 15" MacPro)
If your left-click finger is resting on the left side of the mouse when right clicking it registers as a left click. Back and Forward are achievable with two-finger dragging to the left and right, but what about middle clicking?
I agree that it seems pretty magic, but at the end of the day different physical buttons are preferable to a single flat surface that affords everything; The mouse gives you no physical hints on how to use it.
I thought it was too flat to be comfortable. I'd love to be able to use gestures, but with my limited demo, I found my hand was cramping up.
Maybe I'm just use to those nicely contoured Logitech mice, though? Now that I think of it, the Magic Mouse is probably less "resting" and more "pushing" when compared to other mice...
I bought one for my wife, and ended up stealing it because of the momentum scrolling.
It's not as nice of an input device as Apple's trackpad, but it's my favorite mouse to date. (and the first Apple mouse that I actually enjoyed using.)