There’s a whole bunch of assorted fixes, mostly (it appears) for reporting services, a couple of T-SQL fixes (including one for the merge statement which sometimes won’t enforce foreign keys), a few analysis services fixes and a couple for the tools (mostly intellisense).
Overall, there doesn’t appear to be anything too major in the fix list.
The one really interesting thing about this fix is that it can be run before SQL is installed. If it is, updates setup files will be placed on the machine so that when SQL is installed, the fixed setup files will be run and not the ones on the DVD/download. That’s a really nice feature.
Bob Ward posted a whole blog post on how that works and how to go about it: How to fix your SQL Server 2008 Setup before you run setup…