I haven't even begun to use Freenas yet, but I plan on doing so very soon. I have done a lot of research, I use plex as my daily driver on my windows machine and I've never been let down. I have used it on linux as well and the configuration files are very similar. I also have a few roku boxes, and all android devices which completes my bias. I have heard good things about XBMC, I've just never needed anything other than Plex. It runs it's own mini-dlna from inside the server, and worked fine on my really slow LG 3d TV, and pretty much every device I've thrown at it (I don't play with iphones) ; however, I prefer the look and feel that a roku box provides along with a remote. It seems to be one of Plex's best friends.