I recently picked up a Razer Diamondback 3G as I needed a new mouse. I saw this mouse, and it looked sleek, sexy, and got good reviews, so I jumped.
Opening the box of the Diamondback I was impressed. It came in a very well packaged box with instructions, booklets, drivers, everything. Very well done packaging. Installing the mouse was a blast. I didn't even have to install the software (however I did anyways) and my PC picked it up instantly. It was simple to adjust the speed and settings from the computer.
The mouse feels very nice in your hand, however, if you eat at your computer or don't wash your hands after you eat, the mouse can feel odd because of the coating. It can also be stained easily, so be careful. There are a lot of useful buttons on the mouse for various applications as well as adjusting speed. The scroll wheel is fast and works well, and the DPI of the mouse can be adjusted as you see fit.
Overall, the mouse is very good. I would recommend it to any gamer, and even just regular users.