Just like they are with fighters, most people take too extreme of a position on Dana. Some people pretend he's God's gift to combat sports, and don't ever want to call him out on his BS. Other pretend that he's done nothing but keep the sport from growing.
My take: He's a decent guy who really loves the sport, and probably never thought that he or the UFC would be where they are now. He seems like a passionate man, who's great to have as a friend, but sucks to have as an enemy. Unfortunately, he often oversteps the boundaries of being passionate, and he acts like a child throwing a tantrum when fighters, judges, or reports piss him off.
Ultimately though, I think he's something of a perfectionist and takes his task of delivering fans an exciting product very seriously. Naturally, it drives him crazy when others don't seem to take it as seriously. With the exception of not wanting to do TUF at first, I think he's an astute businessman, and he's helped the sport grow immensely. At the end of the day, if he's growing the sport and treating his employees well, he's cool with me.