I’m "playing" with Office 2003 and the overall feeling is rather good. I’m surprised though that consistency across applications is not more advanced by now. How is it that Project has just one level of Undo, or that its row grouping feature doesn’t work like Excel’s? (In Excel you can group/ungroup all your groups with a single click, while Project’s outline mode is much cruder). Or why is the Redo feature available only (to the best of my knowledge) in Powerpoint and Word?
Project and Visio do feel like Office applications, but for Microsoft to successfully upsell users to the fatest and latest versions of its suite, integration and consistency really need to go into the smallest cracks. I haven’t even looked at OneNote or Infopath yet, and I don’t even plan to bother with Frontpage (though I hear it’s significantly better than in the past) so I can’t comment on the whole thing yet.