I've only seen Adric in "State of Decay" and "Warriors' Gate," but I had the same reaction: "This is the most hateful companion ever? He's...fine." (Of course I also don't understand what's so horrible about Dodo Chaplet, so take that into account.) Though I keep hearing he gets worse later on. I haven't seen "Logopolis" yet, because I like Four too much and I'm chicken, but I like the sound of his regeneration into Five.