I recently got a G7 and I love it. Being able to charge the spare battery whilst using the other one is a great idea, and it only takes a couple of seconds to change the battery when it runs out. You can even make it give you an early warning when the battery is down to a set percentage (which is also customisable) so you can change the battery after pausing the game or taking cover, rather than it coming as a complete surprise.
It's silky smooth across the desk too, due to the teflon coated pads.
For me the maximum 2000 dpi is way too sensitive, having upgraded from a 400dpi mouse, but I can set 5 sensitivity levels of my choice and change them on the fly. I use 1200dpi as that feels right for me, but you can have what ever you want.
The only minor gripe I have is that the middle mouse click feels a little lack lustre. It's only a small issue, and probably just something I need to get used to, but it doesn't feel as positive as my old microsoft mouse.
Anyway, I recommend the G7, well worth it
