RC 2 is a release candidate. It means we thought it's stable enough to be a release, but still needs some real testing.
In the 1.2 RC 2 known issues, you will find all issues that we are aware of. Some of them with fixes.
This list is smaller than CB 1.1's current list of bugs, but we want to have them fixed for stable, and still have some hundred threads to catchup.
The main new features of CB 1.2 are described on the front-page articles of this site.
1.2 RC 2 allows you to do all what CB 1.1 does, and quite more.