Cool benchmarks. The only real difference was at 1600x1200 @ 4xAA/8xAF, (the rest all appear to be engine/cpu limited) and even then (aside from the 6800), the difference was pretty small, and all are still above playable framerates.
ATi seems to have the upper hand with the Source Engine, but the difference was miniscule between the top cards. No where near as the significant difference between the D3 benchmarks.
Though, as the reviewer said, HL2 will be more demanding, perhaps we'll see different results when HL2 is offically benchmarked.