Coming up in the next few days will be benchmarks of Radeon Gallium3D using Mesa 8.1-devel compared to the recently-released Mesa 8.0.1 and the previous releases of Mesa going back for as long as the R600 Gallium3D driver has functioned. While Mesa 8.1 has just been in development for about one month, there's already some interesting improvements for at least Radeon Gallium3D.
While you'll have to wait for the full article for details, here's a preview of the current Mesa 8.1-devel Git results from a Radeon HD 4870 (RV770) compared to Mesa 8.0.1. The two tests are of the DarkPlaces-based Nexuiz and Xonotic games.
The only change between test runs was switching between Mesa Git master and the Mesa 8.0 branch as of this morning (22 February). As you can see, what's building up for Mesa 8.1 is already 12% faster on average for Nexuiz. At a resolution of 1290 x 1080, the Radeon HD 4870 is a remarkable 46% faster with Mesa 8.1-devel over the just-released Mesa 8.0!
Xonotic on Radeon Gallium3D is also significantly faster on Mesa 8.1-devel. Obviously these performance improvements are welcomed by Mesa/Gallium3D Radeon users. Stay tuned for the full article coming up in the next few days. For now you can read how to increase the open-source Radeon graphics performance through other means like HyperZ, enabling PCI-E 2.0, and other changes. Compared to the proprietary Catalyst driver, however, it's about a half-decade behind.
You can explore more of this data on OpenBenchmarking.org from 1202226-BY-DARKPLACE44 or on your local system by running phoronix-test-suite benchmark 1202226-BY-DARKPLACE44.