Microsoft makes really great mice. Apple just can't seem to get it right.
I've bought four "mighty" mice since the launch, assuming that the bad one I got was a one-off. They are all bad. The little ball thing that lets me scroll sideways works pretty well for about a week and then it starts to get intermittent.
All the tips about cleaning say to use a wet, lint free, cloth and hold the mouse upside down. It works a bit but doesn't fix the problem.
After much frustration I paid just AU$19 for a basic optical Microsoft "comfort 3000" mouse from Microsoft and it seems excellent. Thinking back, all the Microsoft mice have been very good.
Apple has produced some real lemons in the mouse "space": remember the puck that came with the original iMacs? The subtle second button has always annoyed me and when I see others trying to use it with less care than me they just can't get the second button to work reliably.
The mouse is so important to the use of a graphical computer, it's time to make one that really works.
I wonder if Vista will become popular due to the Microsoft mouse "halo" effect?