Well I took the plunge this weekend and upgraded to the beta 1 of Office 12. I was nervous that it would be a nightmare what with having to uninstall Office 2003 first and then install the beta, but a colleague who has already "made the jump" said there was an upgrade option, which duly appeared and which I took. After leaving my machine alone for a while, I came back and it was apparently all done!
I fired up Word (my most-used Office app. after Outlook) and admired the new toolstrips. Everything appeared just dandy. I had seen it before as I had installed the beta on a VPC image to play with it; it was dog-slow though so I didn't get very far with it. On my main machine performance was fine though; not noticable much slower than Office 2003 had been so that was my first concern put to bed.
First problem: Outlook failed to connect to the Exchange Server it was configure for. It only worked when I was VPN'd in to the corporate network. A quick search of the Intranet didn't provide any answers so I fired up the Web version of Outlook and used that all day until I had lunch with the same erstwhile colleague who had already "made the jump". He mentioned another internal site I hadn't tried and there, lo and behold - I discovered that I needed an update from http://support.microsoft.com/kb/908521. Once installed and rebooted Outlook now connects like a champ.
I like the way in Outlook you can click on a tab in an email message that has attachments and see the attachments' contents in-line. I think the new toolbar ribbons are very efficient uses of space. There is also a rather nifty "To-Do Bar" that has appeared on the right of my Outlook workspace that gathers a lot of information from emails and my Calendar in one place. Nothing to not-like, yet; no crashes, anyway! I'll keep exploring and let you know.
So one day in and so far, so good...