I'm very unimpressed with Office 2007, but there are some good things. Word 2007, if you use the new lock-in proprietary never-extract-your-data nobody-can-read-it XML file format has some fixes to its primeval style and formatting problems. Excel 2007 is still Excel. Outlook 2007 fixes some ancient bugs (if you sort a category view it no longer breaks the view) and is only somewhat more sluggish than Outlook 2003. It might even work better with Sharepoint 2007. PowerPoint 2007 is as frozen in time as every version of PowerPoint since 1997 or so. 
And then there's Microsoft Access 2007.
I've been using this software intensively for months now, and it's really bad. We're switching back to Office 2003 and Access 2003. (Shades of everyone's Vista to XP regression, but we weren't dumb enough to do Vista.)
The way I use Access makes very heavy use of complex queries and some embedded functions with large data sets. In this domain Access 2007 added nothing of value and has some serious regressions. Access 2003, for example, had some ability to fix-up queries when column labels or even table names were revised. Access 2007 more often breaks the links and destroys the query builder view.
All the problems with Access 2003, like the fragility of links to external data sources (no relative links for example), remain. The only minor advantages are better handling of Sharepoint (SQL Server) 2007 exotic data types.
It's probably a bit slower too.
I've seen some regressions in my day, but Access 2007 is the biggest regression I've run into since WordPerfect bombed its Windows transition (with a bit of help from Microsoft of course).
Don't use this turkey.
 How could they not fix the "custom slide show" UI? PowerPoint source code must be seeded with antimatter mines.