I bought the Razer mamba 2012 edition around the time battlefield 3 came out. My old mouse was already dieing on me.
Hardware
The packaging the product comes in, is amazing.
As far as I can see there are no apparent changes from a visual perspective to the mouse. The main change though is the longer battery life and the Phillips twin eye sensor.

Ergonomics
For me this mouse is very comfortable and I really enjoy using it, but many of my friends don't enjoy using it and prefer a mouse like the gx9. My advice is testing a mouse in a shop or at a friends place before buying it.

Design
The design is amazing and even lighting and charging looks really cool, but it is not really important for gaming mice.

Gaming
The most important factor in a gaming mouse if the gaming. I have played many games and I have to admit it is amazing with some drawbacks. Every time I lift the mouse it will want to calibrate it again for the surface, sometimes it can happen that it will take some time to recalibrate. It really happens very seldom (until now only twice).

Breakdown to the score
So why did I only give this six stars? First of all the price is 129 dollars, which is very steep and for that price I would look for the cheaper version the Deathadder or the non 2012 version. Furthermore wireless mode works very very well, but as the dock has to extra power supply, it will stop charging when the PC is off and that is by far the only moment you don't use the mouse. Furthermore the random calibration lags it has is annoying. It only happened twice, but for that price I don't expect something like that to happen. Overall it is a very good mouse and and can be considered by every gamer.