It isnt light, but i never lift it while gaming or doing other things. The only time i lift it is to put it on the charger and come on, its a mouse. It is heavier than some but I dont find the weight to be a problem at all. It glides across my mouse pad just fine.
Ok, this mouse is awesome. It is really sensitive so that will take time to get used to, but other than that this mouse rocks. It also has web browser things so I can go forward or back with the button in FF, and alot of other things, AND A RECHARGER!!
15'' Macbook Pro
Intel Core 2 Duo 2.16ghz
1GB DDR2 SDRAM
Windows XP/Mac OSX 10.5