I thought I'd throw in my Windows Sharepoint Services experience (which is anecdotal, so may not be representative of all WSS installations...OTOH, maybe it is!).
I've been a user on a WSS site for several months now, and I have to say that performance sucks. What the developers did was essentially copy the information and functionality of an existing ASP intranet site and put it in a Sharepoint Services site, using the portal features and so forth. I'm pretty sure they used similar hardware for the new version of the site.
As an intranet site, its audience is limited, with a max possible number of users under 200, and I'm pretty sure that many times I've been using the site, I've been the only one there. Response is consistently terrible (and I mean consistently...I've never had any page come up fast on this site), much of the functionality sucks (for instance, using the WSS Discussion functionality as a Forum...awful idea, and reflects the designers' lack of experience with Snitz, vB, YaBB, etc., etc.).
I would advise anyone who thinks they might be interested in using WSS to wait and see. Let some other folks work out where the problems lie, write a book, give MS feedback on how to make it useful, etc. Unless you're just doing it for experimentation and playing around, it appears to me that you'll be disappointed with both its performance and functionality.
But hey, that's just one man's opinion!
