I bought this mouse off a friend in college and I still have it. This mouse is extremely comfortable and uses an infrared sensor instead of a normal laser like most mice do today. The anti-slip grip on the Razer Diamondback 3G Mouse is an excellent component day in and day out, works like a charm. The green hue that it gives off fits perfectly with my computer and is the sole reason that I bought it in the first place.
One of my favorite features of this mouse is the on the go sensitivity selector. By holding the side button and scrolling the middle mouse wheel, no matter what you are doing, the sensitivity of the mouse changes. Here is a screenshot to show you what pops up on your screen.
Overall I must say that this is one of the best mice I have ever used. It still keeps up with other mice in the market today and has an excellent chord length. The price was just right but alas it is now discontinued so if you want this mouse, I would suggest picking up the Razer DeathAdder, its close cousin.