I run a small consulting business dealing with multi nationals, and need to be on the leading edge of visual presentation, and analysis. Having been a serious critic of Microsoft, even swapping to a mac at one stage, I'm a convert. This new suite allows me to achieve higher levels of finish than 2007, more easily. The ability to mix graphics into documents, including spreadsheets has been strongly improved, with more common functionality. The micro charts in Excel allow you to create dashboards without using external plug ins.
In general the functionality feels more available, particularly in formatting. Setting out pages in Excel is a bit of a pain to begin with, and printing commands take some getting used to.
One real revalation in this release is Outlook, which now has far broader capabilites in terms of maintaining multiple accounts, and connecting to various sources of mail. The other shift between this and office 2003/7 is the improvement in web based collaboration, which I am exploring with my networked colleagues.
The install was a hassle on Vista SP2 and refused to register. The usual torture contacting Microsoft ensued, and eventually they sorted it with a new product key, but it was a pain.
Other than this, I'm really pleased. Very bug free, this appears more stable than 2007 in advanced use. Lots more power, and much prettier, I reccommend it.