Vindictive SOB aren't you?
Hey now, some people like playing spellcasters...
Seroiusly though the GnG rules seem that they would work better with D20 Modern then any sort of fantasy game. It's awfully difficult to play fictional heroic when ambushes become the preferred method of attack.
I used to be all about the realism, but when it started interfering with the fun I started slacking off. Now don't get me wrong, I think the GnG rules are beautiful piece of work, but I probably won't use them because that's not the tone of game I want to run. I have had TPKs, but the fights that engendered them were awesome and took a while to play out, rather than smack dab, body on slab like GnG strives for.
I have played out three combats with AU characters
Human vs. Giant (3 lvls Giant)
Human vs. Spryte
Giant (3 lvls Giant) vs. Spryte
All were warmains (ECL:4th level) same equivalent equipment
The larger turned the smaller to goo every time. The Giant vs. Spryte took the longest because of the Spryte's flight, then the Giant threw a dagger...