Those sites were straight WSS 1.0, a major pain in the bum to actually make it look that decent. The issue we had was that for our users to actually be able to do anything, they had to be on IE6 (IE5.5 on MAC was "ok", but not complete). FireFox, Opera, Netscape, etc... none of those would work good with WSS 1.0. I have no idea, but I'm sure they've fixed it by now.
We were able to set up some templating where a content manager could create their own pages and have it apply the correct template and all. Funny thing is, all the forums and everybody else was telling us "you can't do that with WSS", yet we managed to accomplish it. Was it easy? Hell no. Would DNN have been easier, oh yeah.
Again, my experience with WSS is limited to version 1.0 which was, for all intents and purposes, a piece of crap.
If you have access to WSS 2.x (which if you have Windows Server 2k3, you do), I'd say create a portal in WSS and set it up side-by-side with a DNN portal. Take notes as to what it takes to create each one and compare the setup process -- which is easier, which is more intuitive. Then go through it and evaluate it "out of the box" to see how close it gets you. Once it comes to customizations, it will take just as long to make a webpart for WSS as it does to make a module for DNN. I think skinning is probably "easier" in WSS now than when I worked with it because it supports master pages, but DNN has supported some nice skinning like that for a while.
The fact of the matter is, you need some heavy document management and there is *nothing* for DNN out there that compares to WSS or SPS for that. There are some great products out there, but they do fall short (this is as far as my knowledge goes... I could be wrong).
Of course, you are right in saying that this is a DNN forum and so of course people here will be biased towards DNN. People on a sharepoint forum, should they ever actually answer you, will be biased towards sharepoint. The luck of the draw is that with DNN, people actually do answer now. 