Team Fortress 2 isn't the most demanding game there is for mice overall, but when you factor in the scout; a fast mouse makes the difference between becoming bat bait or owning a scout. For me the G9 was a welcome guest in this area, my prior mice have done a good job at trying to keep up but the G9 at 3200DPI with 1000hz polling just kept me on top of them step for step and really there's not much of a better feeling when you start laying down scouts, unless you go to the dark side and play one yourself using it.
The G9 keeps on par here with the competition, being able to program my buttons is a wonderful thing, the macro feature wasn't that useful in TF2 although I could see how one might have one set aside for engineers and building. The MicroGear was a feature that came in handy for quick swapping as the last weapon swap isn't that handy with such a variety of attacks, often is it that ammo is short lived so the next handy item needs to come up fast to win in a showdown.
The map testing was diverse, using the entire scale of maps in TF2 for this one given the mode of play varies, it's hard to scout the whole time or have a good run as a heavy if the map isn't really designed to allow for it, I think one of my favorites was using skyscraper to bounce around in, while others seemed to have trouble placing their next sticky bombs in place, I was able to set and prep fairly fast and get through the sections. In general the mouse was giving me a boost to my reaction time over others because as opponents attempted to whip around and strike, I was already there and landing critical attacks. I liked the improvement that also came to the Soldier and Sniper classes, being able to lay accurate shots on the fly is a really nice change of pace instead of doing a very random "I hope this really lands" approach to fighting.
In the field test, the G9 took some hits though, being able to fully compress my hand onto the mouse was a nice thing and really I was only getting that out of the G5, Deathadder and MX518. When gaming runs for hours like it can, things need to feel a bit natural; while I can game for long periods on the G9 it's not carrying the same feel even with the grip change. Between the cast of 3 I'd say the revised G5 had the lead, without that the Deathadder had a close second on that spot.