I chose Mezzanine twice because community support works better than the other options (check GitHub issues and the mailing list traffic and feedback). I can't compare them technically side by side but I found easy to extend Mezzanine just looking into Django docs instead of looking at the specific Mezzanine implementation.

One point that put me in doubt in favor of Django CMS was the support for editing single page sections, you can do that in Mezzanine but it is not "native".