I used Office 2007 for about 6 months in conjunction with the free version of RibbonCustomizer. The add in worked great but for the life of me, I couldn't see anything in 2007 that was better than 2003. 2007 was very slow for me and as I said, I needed a 3rd party utility to get the functionality I wanted. I went back to 2003 (except for OneNote) and I couldn't be happier. Very snappy and I prefer the menus to the ribbon.
This has been my experience exactly. Add in Office2007's gargantuan memory footprint, its weird behavior sometimes with extra-huge Word tables, the needless reorganization of the interface leading me to hunt ceaselessly for features I used in Office 2003... and I'm glad I retrograded.
The good news: internally, from a COM/object perspective Microsoft did an excellent job of not breaking anything. I no longer even test new builds of my software against 2007 unless a customer reports a platform-specific bug.
Now... following this trend, should I retrograde to Office 2000? The file formats are (mostly) the same and that 12 megabyte(!) memory footprint so very sexy.
Anyone run 2000 vs. 2003 recently? What would I miss?