This one I don't really understand. I've talked to a bunch of beta testers and even worked for 4.5 hours on the beta here. I found bugs as have many of the testers, but to all of us they've seemed trivial; at least by appearance. It might be that there are simply too many of them and the degree of "badness" has nothing at all to do with it.
To me, Office 2007 (as I know it) is not a compelling product. However; I know some Office power users who find it very much one. It is a matter of outlook, I think, combined with what you work on and how.
One of my MS reseller friends (no jokes about my consorting with the dark side, please) is toting a laptop around which he lets potential clients use as a trial. He is finding workers at SMBs almost universally find something new in it that they think they will use, so perhaps I ought to go take another look at the beta.