An update about the MX518 vs G9x. Now that I've been using the G9x for a while, I find it a lot more comfortable. It was nice right from the get-go, but now I really like it. On the MX518 I end up pushing my pinky in since the mouse is more narrow and it makes the right side of my hand want to cramp up when I've been gaming for a long time, if that makes any sense. Anyway, thanks for the mouse suggestions!
Ah thanks for the info. I'm not sure if that makes it better or worse. Because I'll still have my MX518 for another rig. I wonder if it'll be difficult to go back and forth between them at all. Ah well, I'm probably over-analyzing a non-issue. Thanks for your comments and help.