The real draw here, of course, is the 15 individually programmable buttons, which can be assigned to up to 160 interchangeable macros with the downloadable Windows-only software. SteelSeries claims to be "working with Blizzard on the development strategy for a Mac solution" which sounds like they've got a whole lot of nothing ready for the Mac-inclined. Right now they recommend setting up the mouse with the third party ControllerMate software.
That's a shame, because the software is the real strength here. You can set up 10 different profiles for your various alts, play styles and situations, with buttons set to dismount, auto target, target self, toggle bags... you get the picture. Unfortunately, with all that complexity comes a bit of a learning curve. It took our WoW-addled intern two hours of running Heroic Nexus to get used to using all the buttons, and he found that even then he was mainly just using two of the macros, with the rest being forgotten more often than not. A heavy macro user could probably use the mouse all by its lonesome and rid their reliance on a keyboard, but that would take a certain amount of skill and determination. The real strength here is Battlegrounds and raids, but it's clear the mouse isn't really about making WoW more accessible or "easy," rather about enabling power users to kick even more ass. The mouse is available now for $99.