I'd agree with your assessment of the past Apple mouse lineup (undeniably shocking), but the Magic Mouse gets a lot of things right. I find myself wishing I had a multitouch surface at my work PC instead of the somewhat clunky but serviceable MS mouse.
For me, the Magic Mouse gets one thing horribly wrong: ergonomics. I use a computer at least eight hours of the working day, and potentially much more than that. If I can't be comfortable using a device, it doesn't matter how awesome it is, I can't use it.
