Allen Browne has put together a nice resource page on Access 2007. I'm not sure I completely agree with the statement about too buggy for serious use--guess that depends on your definition of serious use. As with any major release there are some bugs that slipped through (the team will focus on fixing the critical issues in SP 1) but I feel pretty good about the "What's fixed" list. Most of those issues have been a pain in the side of Access developers for a very long time. Personally, I find it painful to use Access 2003 after spending so much time using the new functionality.
"The most significant release in 12 years, Access 2007 introduces major new functionality in both the engine and the interface. Seasoned developers will discover new things are possible, and casual users will find more things within their grasp.
With so much new stuff, it is no surprise that the new version has many bugs. It will be a great product, but the initial release is too buggy for serious use."
Here is my favorite section:
Every time you opened your database, Access 2003 tried to convince you that was a bad thing. Access 2007 solves this by introducing Trusted Locations (Office Button | Access Options | Trust Center | Trust Center Settings.)
Developers often coded to disable the mouse wheel so it would not scroll records in Form view. Access 2007 scrolls in Datasheet and Continuous view, but not form view. Use the new Mouse Wheel event if you want the old behavior.
Updated post with whats fixed information 1/20/2007.