I've gotten a lot of questions from customers who are moving to Office 2007. Most of the questions are around items like the value of the new Office UI, ease of deployment, and integration with MOSS 2007.  The best place to get information on these topics is the Forrester report: http://www.microsoft.com/presspass/itanalyst/docs/07-17forrester2007office.aspx.  The report does a good job at providing an independent voice on Office 2007 and its benefits and limitations.

The word I'm hearing from customers who've moved to Office 2007 (and MOSS 2007) is that it's well worth it.