Hi guys! I just installed this and wanted to check out if there are any performance improvements. Maybe we can all test this one out.
With my 5850 @ 960/300/1.174v | poclbm 6.27.2011 + aoclbf 1.74

Catalyst 11.7 = 389-393 Mhash/sec.
Catalyst 11.6 = 390 Mhash/sec.

Some guys reported improvements on OCL performance here http://bit.ly/iPSObE (Post 41).

It's a new AMD APP runtime as well as driver.  Here is the download link also from the thread (thanks for users out there) 
http://bit.ly/kDIiWo

Enjoy!