WoW player? Then how about the Razer Naga
That thing is a bit ridiculous.
I can't comment on the Mionix mouse you linked, as I have to say I've never heard of the name. *ducks*
I've used the Saitek RAT mice before, and I wasn't that big a fan of them. Then again, I wasn't much of a fan of my G9 until I used it for a few days.
I'd recommend checking out a few others:
In the end, if it fits your hand comfortably and provides the tracking speed and accuracy that suits what you want, go for whatever you want.
Edit: I found the Mionix Naos 3200
on Newegg. A few dollars cheaper, and a few reviews.Edited by Untame Zerg - 1/1/11 at 4:52pm