So after taking a Ghost snapshot of my machine, I was feeling a little brazen and decided to install Office 2003 Beta on my primary OS. I ran it previously in VMWare, but it seemed to be crashing my machine a lot ever since I did a fresh install of WinXP SP1.
I don't use Word, Excel and the others much at home. Most of my time is spent in Outlook, so I'll focus on that for now. There's undoubtedly a ton of improvements, both obvious and subtle, and I'm sure I haven't even scratched the surface - but I like what I see so far.
One thing I noticed right off the bat was that the junk mail filtering seems better. I haven't yet installed Cloudmark, but now I'm wondering if I even need to. I don't know what algorithm they're using, but it definitely seems to be catching more than I remember it catching in the past.
On the usability front, there seems to be a number of nice, subtle changes. The first thing I noticed was the ability to minimize to the task bar. This is something I wish Outlook has had forever, and, in fact, I bought a great utility called Trayer a few years back to do precisely this. Like news aggregators and music players, the typical usage patterns of Outlook makes this an invaluable feature.
It seems grouping is also on by default now. IIt's actually quite nice when sorting by date. The display is very similar to how Internet Explorer history is grouped - today, yesterday, last week, last month, and other. It's a little weird if you sort by other fields, though, especially when those fields contain only one such item. I wish there was some "smarter" grouping going on.
Another nice feature are the pre-defined search folders. For example, you can now go to a single folder to read all your unread mail, regardless of what folder it's in. You can do the same for items that you flag for follow up.
There is, of course, the standard polish and spiffier icons that Microsoft applies to all new versions, and it looks good. After all, a facelift always makes it seem that much newer, even if none of the features have changed. In fact, I wouldn't be suprised if most of the nice things I noticed now were there before, just didn't look as pretty!
Anyways, I'm sure I'll have more opinions in the future, but so far, my impressions have definitely been very positive!