The most distinguishing feature of the mouse is the four rows of three buttons on the thumb side -- Razer has placed a little keypad, very similar to that of a cell phone (in fact, Wannlund showed us how it could be held exactly as a cell phone -- you can see his thumb dialing in the pictures above), on the side of the mouse for the thumb to press. The pad defaults to whatever you've got bound to the number pad on the keyboard, so setting the thing up is very simple -- just map whatever abilities or actions you want (he told us that it works for any game or app with customizable buttons, and that while it's designed for MMO players, quite a few people actually showed interest in using it with apps like CAD and Photoshop) to the num pad, and then press away.
In World of Warcraft, the functionality goes a little farther. You can either switch the inputs on the mouse buttons to the main keyboard number keys (1-9 across the top), or you can use the WoW addon included on the disk. The addon lets you map any ingame abilities to a series of grid which then connect up to the number pad, along with seven other key combinations (Alt, Ctrl, Shift, and then all of the multiple combinations of those). With all of the combinations out, the addon can take up a good bit of your screen, but of course you can go transparent, or hide them or whatever you need to do. Wannlund told us that Razer would do their best to keep the addon updated, but that it would likely work with future versions of WoW anyway (though of course you'll have to "enable out-of-date addons" if they don't update it faithfully every patch).
In the future, they're hoping to go beyond just mirroring the num pad, and providing the buttons with inputs of their own somehow. But at this point, the buttons are either mirrored to the num pad or the keyboard, so if you want to use all three of those separately, you're out of luck. Still, 12 buttons with eight different options for each is a lot of functionality put into one thumb and three modifier keys.
The mouse itself is a little smaller than even most of Razer's mice -- Wannlund told us that gamers tended to cup their hands up on mice as they play, and that they tended to use less of the mouse, so they actually made less of it. The mouse also has a ridge on the far side from the thumb, where your ring finger can go. He told that in the research Razer had done, MMO players tended to have more downtime than most game players, and so they made the mouse a little more comfortable when your hand was just laying on it rather than actually in the middle of action.
Using the mouse was a little tough, not because I had trouble pushing the buttons (actually, my thumb pretty easily found its way to all 12 of the buttons), but because it was a little tough to map your reflexes to move your thumb rather than the keyboard when hitting abilities. Wannlund says that players will need about 20-40 minutes of play to start getting used to hitting the buttons, and may need more than that to get really good (obviously more time than we had in the demo -- I definitely wasn't used to it after the 10 minutes or so of throwing spells at a target dummy in game that I got to do). They suggest you don't head into a battleground right away, and even as I was just messing around with it, I could definitely see it being an immediate disadvantage in the fast-paced world of PvP... at least until I practiced and got used to it.
The mouse has tiny markers on the 5 and 11 keys (the middle buttons in the second and fourth rows), and Wannlund told us that they're planning to ship the mouse with little raised dots you can attach to the keys temporarily. The mouse runs $80, which is pricey for a mouse, but not overly so for a professional gaming mouse, especially one as specialized as this. If the prospect of moving your quick-keyed abilities away from your keyboad and onto your mouse (leaving your other fingers open for moving quickly or hitting other spells) appeals, and you think you can get past the fairly steep leveling curve and significant training time, the Naga could have you casting faster than ever in style.