I was about to buy the G5.
I like the fact that you can add weight easily if so desired, and the damned low to insane high DPI is awesome also.
How much does the mouse normally weigh? One reason why I prefer corded mice is because of the lesser weight. And the fact that wireless products are easy to lose (I have lost my wireless keyboard... the thing is huge...).
How is the comfort overall? I liked the Logitech Click!, but not so much for the Click! Plus.
Then there's size. I have grown accustomed to the click, which I always have my wrist on my mousepad.
Then there's also the laser sensitivity. Will it work on most surfaces? All surfaces? Mousepads only? I like to use a mouse on both my bed, carpet, and fiber board, with the occasional felt blanket. Can this do that successfully?
My only complaint though...
I never did like buttons at the thumb... ruins comfort and my hands are too big to use them easily anyways. Same with a button below the scroll wheel. looks decently badass though.