While I was playing I decided to grab some screenshots that were requested earlier (no comparisons, though, sorry!).
That brightened grass thing isn't actually a problem. I believe it's a case of the GI fix defaulting to zero, so if you set it to 16 manually you
think it's on, but the next time you boot the game it's disabled (set back to 0).
Here's how that alley looks with GI set to 16 (click for full size):
With GI actually set to 16, it looks pretty much the same as 128. With GI set to 0 (i.e. off) it looks like the brightened grass image posted before.
As a bonus, here's two screenshots of the desert. One sort of like the image Durante posted earlier, and one of the
. Click for full-size (I won't embed the potentially-spoilery one, so click it if you want to see it).
Second image
These are at GI 16. They look pretty close to 128, and
certainly run better. I can't see a reason to use anything higher than 32, unless you've got performance to spare and
really want the
slight improvement.
EDIT: Gah, Steam's screenshot tool + imgur compression really added banding to those screenshots. Well, at any rate, they're enough to show that GI at 16 doesn't change the overall lighting that much.