At this point it seems like Homebrew is the standard -- I frequently see open source projects recommending it in their installation instructions without mentioning Macports.
I also recommend Homebrew to friends and coworkers, for the reasons I already mentioned, and also because it is significantly easier to install. Go to their website and the first thing you see is an installation script. Go to the MacPorts website and you see a link to an installation page partway down. That installation page is very long and lists a number of prerequisites needed for the installation to work. Homebrew does the installation bit way better, thus making the barrier to entry far lower.
MacPorts would need to demonstrate significant advantages over Homebrew to get me to switch back.