I ran across an interesting blog post by Stephen Arnold who is a longtime industry analyst and consultant that spells out the hidden costs of a SharePoint implementation.  The post is here.  While free always looks better than paying for software, I think Stephen hits the spot with his assessment.  A free software framework such as SharePoint is great if you plan to keep requirements very simplistic.  As we all know from our own experiences with implementing content management, that is easier said than done.  If you have more complex requirements, maybe a packaged solution such as RSuite makes sense.  Your company's approach to projects, culture to build versus buy, and several other factors need to be considered before selecting a technology and embarking on a content management project.  Whatever approach you take, just be cognizant of hidden costs as Arnold pointed out.  Free software does not always mean it will be cheap to implement and maintain in the long run.