There was a topic over on the driverheaven.net forums where a person had tested various custom driver packages. Omega, Ati cat 4.1, Neutral, DNA, and Asura. He/she did not do any image quality testing, but actually found that many of the driver packs offered increased frame rates/scores/etc over the standard catalyst pack, albeit a very small percentage. Also, almost all of the packs took a hit in one test or another. Im running the Asura 4.1 catalyst right now and I am very happy with the performance and image quality.
Edit: Looks like the new Omega's have a version of radlinker built in. Nice suprise.