I have both, they are awesome! The G7 IS a gaming mouse, don't listen to people that say wireless willl never be for gaming. I heard Logitech is comng out with a different colored G7 instead of the Dark green. The G15 has a great feel to it, the keys are kind of grippy. The CPU monitor on the keyboard also supports dual core processors, the CPU bar is split into two.
AMD X2 4400
2GB OCZ Platinum
Caviar 320GB SATA2
SUSE 10.0 64Bit-WindowsXP x64-Vista 5270 64Bit