I pretty much know it for a fact that this will get deleted, but in case it does slip through moderation, I hope people find it through Google and not waste their time on Alfresco.
To be fair, out of the box Alfresco worked with minimal tweaking, except, of course, Open Office integration is broken and swftools need to be installed by hand. The old UI is crummy and confusing, but Share looks pretty good, so if you don't need single sign-on or file sharing, it's a reasonable choice.
If you do need single sign-on, then read on (the following applies to Alfresco Labs 3 Stable):
1. NTLM integration is busted in Share out of the box, in several different ways. For one thing, single sign-on is only possible with plain NTLM. This means that you won't be able to log into the site from vanilla Windows Vista, since it requires NTLMv2, which gets you into the endless login loop in both the site and file share. This is epic fail #1.
2. Once you remove single sign-on (leaving NTLM in place), things kind of work, except your username and password are sent over the wire in clear text since you enter them into a plain web form. I said "kind of work" because if you try to log in directly into Share, you will discover that it's busted (shows an error message) - you need to log into Alfresco proper first and then log into Share. This is epic fail #2.
3. So one might think that if NTLMv2 doesn't work, Kerberos might work instead, right? Not so fast, bucko. After following five screenfuls of Wiki instructions to the t (and some head scratching, since instructions are incomplete at best) I got Kerberos running without errors. Except Alfresco, for whatever reason, thinks I'm "guest" and shows me a completely blank page when I hit the site. This is epic fail #3.
There are more. Alfresco is WAY overengineered for what it does, produces unintelligible stack traces 150 (and more!) levels deep, and often does not tell you what failed when something fails. Frankly, I'm glad I got the Labs version before talking to the higher ups about forking over the money for the Enterprise. I totally expect the same issues to be present in the Enterprise version as well, so we might as well save ourselves a headache and go with Sharepoint instead.