Personally I don't know what all the nay-sayers are on about. The Mighty Mouse works flawlessly for me. It performs exactly as it should. It's a great mouse and I have no regrets ever buying it. I've had many BT mice in the past and none of them match up to the Mighty Mouse.
Others either skip, have lousy tracking, are not real accurate or run through batteries too quickly. The Mighty Mouse is fantastic. Batteries last for ages, it's precise, never skips and is easy to use. I've read people complain about the right click, but I've never had a problem using it.
I say go for the Mighty Mouse.