I like Children of Earth, mostly because Gwen stops going "Jack, Jack, look at me, notice me, Jack!" for five seconds to actually be a badass and pay some attention to her husband. (This is the main reason I don't like Torchwood: all of the characters are these nihilistic jerks who treat everyone around them like disposable playtoys. Children of Earth is better because they actually put some meaning on their relationships.)

I have yet to see Miracle Day, and I probably won't.