First order of GFore 4.1's arrived.
I typically only wear Adidas and current Codechaos are 12.5 so ordered GFore 4.1 in 12.5. They fit exactly as they should or "true to size" IMO. When the 13's I ordered (after reading on the GFore site to size up) I'm sure they'll be 1/2 size too big and will be returned.
My experience, yours may vary.