Info-Mac

I absolutely HATE this mouse. I bought my macbook pro, time capsule and wireless mighty mouse all at once. Of all the purchases, I regret the mouse. It hangs suddenly for no reason and then picks up again. The battery life is terrible since I go through a pair of AAs in about 2 months. Most importantly is that scroll ball. It gets filthy almost immediately and there's no real way to clean it. The recommendation is to turn the mouse upside down and rub it on paper to clean it up which works for about 3 days before it stops responding in on or multiple directions. And you can forget about simplicity in taking it apart to change the batteries. I definitely am a Kool-Aid drinking Apple fanboy these days but that mouse is just terrible.

Wireless mice are the worst. All wireless mice display essentially the same behavior as you described.

The ball on the other hand, yeah it's great when it works, but often doesn't. Frequent vigorous cleaning usually helps, I went through two mice within months but now I've had the same one for over two years.

I must admit, I've had few problems with my WMM (aside from the issue that the ball more often than not refuses to do what it's meant to).
I've never experienced the problem with the mouse hanging, although I do think it interferes with me being a guitar hero legend on the wii if it's between me and the tv. For some reason I miss alot more notes when anything else with bluetooth is in the way...

Some things are just better with wires.

I couldn't careless if it was wireless or not. Either way the Mighty Mouse, sucks.