I've heard horror stories about Outlook 2007's speed. On one machine, it's incredibly slow, but that machine needs more RAM, and I'm waiting for the IT guys to add that so I can see what the performance is like. On the other machine where I run Outlook, it runs well, but that's a dual-core 3.2GHz machine with 4GB or RAM, so everything runs well there.

The biggest thing I have noticed is a tendency for the little machine to stop dead for several seconds every so often. Whether that is Outlook, or just paging to disk because there isn't enough RAM or what, I don't know.

Also, it isn't clear to me whether the slowdowns people are reporting are due to Instant Search, or to Outlook, and I don't know whether it is an issue with Outlook on XP and whether it works better on Vista, which is more tightly integrated with all of Office 2007.

So there is plenty to say on the subject, but I don't know have definitive answer myself. We'll be keeping an eye on this aspect of upgrading and let you know as we learn more.

Conclusion
These helpful features are some of the things that come to mind when I think about Outlook 2007. There are lots of other productive (and fun) changes that I could talk about as well. This really is a significant update from Outlook 2003. Despite the new-product hassles and things that I have complained about, Outlook 2007 continues to grow on me. I like it and you will too.