Radeon Gardenshed DRM + Gallium3D Benchmarks
At 1920 x 1080, World of Padman is barely playable on the open-source driver with this range of mid and high-end hardware.
Urban Terror at 1024 x 768 is suffice on the open-source drivers, except for the Radeon HD 5450.
It will likely be a while before the R600g driver becomes more competitive against Catalyst in terms of OpenGL performance.