I just installed Catalyst 5.12.
Conclusion: The best Catalyst version since 4.12 without questions.
I gained 91 3DMark05 points with a mere drivers change (my new score's compare link has been updated in my signature). That's with an over-clocked status.
And I gained 82 points at stock speeds.
3DMark05 with 5.11 @ 550/550: 7828
3DMark05 with 5.12 @ 550/550: 7919 (score in link from signature)
3DMark05 with 5.11 @ stock: 7266
3DMark05 with 5.12 @ stock: 7348
I really like the driver so far.
Not to mention that Catalyst Control Center finally seems faster and more responsive. I'm using .Net Framework 1.1 with Service Pack 1 for it, in case someone might wonder. I wanted to get the "Driver Only" package, but I decided to give CCC a chance, since I did not download Catalysts with CCC since 5.9. So, I'm not 100% sure about CCC being faster, but ... so far, it looks like it is, even though it wasn't actually mentioned in the change log as optimizations for it or anything, so, I'm just assuming it is.
One thing is for sure, I can confirm, at least on my system, Catalyst 5.12 is the best version I've tried since a long, very long time.
And my horizontal tearing is gone in Day Of Defeat: Source. It might have been fixed simply by changing drivers or something else, I'm not sure on that one too, but it's gone now. I'm happy about that as well.
To anyone here using ATi products supported by the driver, I highly suggest you install it and give it a try.
Oh and, finally, that's on a Single-Core CPU system for the moment. Even though it was optimized for Dual-Core CPU's, it seems it is also faster, perhaps depending on system configurations and others, on Single-Core CPU's.