I have a Naga Molten myself and I've never had any problems with it.
I use it constantly (4-10 hours a day) and it is still going strong for nearly two years now. I've never dropped it or subjected it to extreme forces, so I can't tell you how well it stands up to rough abuse, but I don't see why any gamer needs to abuse a mouse....
As far as the buttons and their WoW Addon, it works and works well, though I don't use it anymore. I wanted to try mouse-turning, but after several long sessions I just couldn't do it. I don't know why, it just feels so... awkward and unwieldly. I wound up taking 3x as long to perform simple tasks and I didn't see all THAT much improvement in my abilities in combat.
In fact, I found that I was becoming very heavily distracted and found myself missing GCDs and forgetting abilities in rotations (Ret Paladin). I'd forget Inq, or Art of War would pop and I wouldn't notice it for several seconds, wasting half of it, etc.
I eventually forgot about it.
But while I was trying to do it, the buttons seem to work well, though I had some trouble with remembering which button is where. I found 4-6 and 7-9 easy, but 1-3 and 10-12 I'd occasionally "miss" but then that's probably just me.
The mouse was easier to use than I had anticipated, its just the mouse-turning thing that was throwing me off bigtime.
IMO, it is worth the money.
Also, the mouse is VERY sensitive if you max out your Mouse Sensitivity. Every time I sit down at mom's computer with some random $10 Wal-mart Mouse, I find myself groaning as it takes 3x the time for the mouse cursor to get from one edge of the screen to the other. The Naga really does provide excellent performance in that aspect, too.
The ergonomics are also very nice, my hand fits right on the mouse and my fingers rest just right on the mouse's left and right mouse buttons, though if you have huge hands, you might find it awkward; the mouse isn't as big as you'd expect from the pictures. It is more round and fat than a Wal*Mart mouse (Logitech and the like), but yet it is about the same legnth. I found it fits my palm perfectly.
So... anyways, my personal opinion:
I love my Naga.
Also, if you like Razer's gear.... the Banshee Headphones kick serious ***. LOVE them.
EDIT: Oh wait, there is one problem.
One teensy problem that is easily fixed if it happens. Sometimes a hair will get caught in that rubber ring around the optic sensor. If that happens, your cursor will stop moving horizontally or vertically depending on how the hair gets stuck. All you have to do is either blow at it, or use your finger to clear the hair. It is fairly rare this happens, but it does once every other week or so. No big deal really. It probably only happens because of that little rubber ring around the optic sensor that most other mice don't have.
Edited, Oct 17th 2012 10:06pm by Lyrailis
Edited, Oct 17th 2012 10:09pm by Lyrailis