Does anyone use a trackball mouse?

I've been curious about making a switch for ergonomics and just lack of space on my desk.

• Do you recommend it for gaming? Any guidance on genres that do or don't work? I mostly play real time and turn based strategy games or point-and-click style games such as Diablo on my computer. I don't generally go in for twitchy FPSes, but I'd like the option.

• Opinions on index vs. thumb?

• How long was the adjustment period to get used to it?

• Any recommendations on good ones to buy?

• Are there any advantages I'm not thinking of besides just being better for my wrist?

• Disadvantages besides, potentially, being less precise than a mouse?

• Are there any tradeoffs with going wireless?