I'm producing a site for a client at the moment, and it quickly became apparent that I'd have a number requirements that would lead me down the CMS path:
To be fair to the customer I couldn't really suggest that I do everything from scratch when there's plenty of open source and commercial CMS's that can do the job very well.
I do .NET - so I'm sure there's plenty of great CMS's for other platforms, but I'm not about to use this as a re-skilling exercise, charging a customer for the pleasure (as I need to do some more 'significant' development around the site, so will be using .NET for that).
What follows is a personal view based on my requirements and my experience (rather than extensive research into each product).
DotNetNuke
This was the first one I considered as I'd had dealings with it a few years ago (a dev 'community' site at a previous employer). After playing with just about every module on the planet at the time ('cos you do), we realised we just needed a blog, so converted to Community Server as that seemed a bit less cluttered. (BTW if you want to run .NET blog without SQL Server (like me) then DasBlog's what you want.
Pro's
Con's
MojoPortal
Until a couple of days ago I'd not heard of this, but the performance discussion (above) sparked my interest. It's clearly got less out-of-the-box functionality and community support than DNN and is lacking more in the documentation department, but if you're after a no fuss implementation then this might be the way to go.
Pro's (from the site - not my experience)
Jury's still out on this one as I've literally installed and that's it. I need to get to grips with the integration and skinning support, as I want to change the default 3 pane layout and remove the left panel, so we'll see how that goes...
Others (That I don't know anything about)
Rainbow Portal (looks like it might be more worth a look in a year or two when there's a bit more support
Umbraco (not all versions free)
So what am I going to do now? Install MojoPortal and see if it 'feels' nicer than DotNetNuke. I'm not really too worried about future support, and upgrades as I'm providing a site to a client who will run with it once I'm done (based on what it does 'now' - and how stable it is 'now').
I'll post the results - or add to the list when I've come to a conclusion after some more research