The shape is different from most mice and takes a good deal of getting used to. Although it allows you to rest your whole hand comfortably across the top of the mouse and is probably more ergonomically correct, particularly for extended use, it doesn't lend itself well to being easily picked up and moved. To make matters worse, the optical sensor seems very sensitive, and was reading movement even when raised an inch or more above the surface. Although neither is a big problem for general Windows use, as you can simply bump up the pointer speed or acceleration to get more travel out of smaller mouse movements, these two issues made for a lousy gaming experience. I was constantly reaching the edge of my mousepad, attempting to lift and recenter, and winding up right back where I started because I didn't get the Naos high enough up off the surface to avoid it tracking the movement.
Additionally, while the thick, braided wrap may seem like a good idea to protect the mouse cable, it also makes the cable more stiff and prone to retain its bent shape. Large rapid movements down and/or to the right would cause it to drag on the rear edge of my keyboard/mouse tray. It never snagged completely or got hung up, but that extra little bit of resistance can throw off your game if you're not anticipating it.
I found the Mionix Naos 3200 online for right around $60, certainly not an unheard of price for a gaming mouse, in fact most of Razer's stuff sells for more than that. However there are more than a few other well-known companies who make gaming mice in the $40-$50 ballpark that could easily give the Naos some stiff competition.
Rating it objectively, OCIA.net awards the Mionix Naos 3200 our Silver Seal of Approval for its functionality versus price. However I ended up pulling the Naos and going back to my old mouse as personally I could not grow accustomed to its shape and feel.