I have a G15 & a G5. Had em both for 2 years now and both are brilliant.
The G15 took a pretty bad coca-cola spill and I then washed it and dried it off with a blow drier, it's still working with absolutely no problem at all. I love the keys as clicking them is very nice on the fingers and the back light is one of the main reasons I bought it, I like playing games in the dark and seeing what I'm typing makes it much quicker for me. The LCD is also pretty useful as I use it to monitor temps for CPU and HDDs, using it for media player while I'm in-game is also quite nice.
The G5 is extremely good. I'm loving every minute with it. Very accurate, I change the DPI pretty much for each game (CS:S is the fastest I use - 1850 DPI, L4D is the slowest I use - 1200 DPI), the weights are bloody brilliant as I like my mouse to be quite heavy and everything is customizable. It's everything I coulda asked from a mouse (and I don't like wireless crap so the G7 is irrelevant as far as I'm concerned).