I decided to just jump in an buy one of Apple's new Mighty Mice and thought I would pass on my thoughts.
I ordered it on Wednesday direct from the Apple online store for a price of £35 (about US$60) which is definitely a premium priced piece of kit but not too offensive. It arrived the following day.
As expected with anything Apple the packaging is pretty cool and the mouse well wrapped up. On initial examination the mouse feels pretty light and plasticy but not poor quality. Installation of the software CD takes a few minutes as a reboot is required.
Once installed going to system preferences allows you to sort out the settings. There are four 'buttons' but not as I expected. The normal two left and right buttons work as with a normal mouse, the 'nipple' for the scrolling is also a button and the two side buttons work together when squeezed. Default settings are left and right set to 'primary button', the nipple brings on Dashboard and the two side buttons are set to Expose all windows. So you have to change the right click to 'secondary button' to use as you might expect.
I have changed the settings so that the side buttons launch Mail and have left the nipple scroller to launch Dashboard but all of these are customisable to launch whatever you like.
Using the mouse (note I have never used a standard 1 button Apple mouse) is pleasant enough and whilst it does not have two buttons it easily senses whether you are left or right clicking. The scroll nipple takes a bit of getting used to and, because it is so small, takes a bit more effort to scroll down a big document. I find that I use tw fingers to make a normal left click and then click on the right to make a right click, this is a new way of working if you havent used an Apple mouse before. I have not had to use the left and right scroll yet so can't comment on how useful that is.
The squeeze click of the two side buttons is again a slightly unusual feeling as you have to be careful not to click the front of the mouse at the same time - but I expect I will master this soon!
It would make sense to have this Bluetooth enabled and I would agree with the previous poster who suggested a dock of some kind to get over the power problems.
Overall a nice new toy that looks more at home that my previous PC mouse, pretty expensive though compared to similar offers but so far I'm pleased with it!