I started out playing on my old G4 1 Ghz, but after too many Zul'gurubs with the weather slowing my frame rate down to almost nil, I spent a little bit and built a Windows machine. That machine was okay, it didn't have slow down issues in zones, but I wasn't able to get things done with it, so my Mac still got a majority of the work. Constant problems with virus scanners and windows updates finally convinced me to dump it and go back to Mac. Have my 24" iMac rocking faster then the PC ever did with a second monitor on it, and use the old Mac for vent. I can have wowwiki up on one screen, WoW on the other, and nothing is slowed down. Dalaran doesn't even affect me. And accessories? Well, some people don't realize this, but Logitech G series keyboards DO have Mac drivers, but even before that, I bought Controller Mate for some other stuff and it works GREAT. So what if you have to configure it, you can have it do more then any other driver can, even entire key sequences should you choose.

As for the claims of instability on a Mac, never encountered them. The only times I ever had that was when I was running excessive beta software. I can also imagine the problem if you use a lot of cracked software, but overall, I have no stability issues.