On my 739ER flight IAH-LAX on Wednesday, the live TV signals were lost soon after we got to cruise altitude. They said they tried to reboot it but it never came back. Initially, I was very pissed since I already swiped my card, but then I found myself really enjoying Nurse Jackie and Californication.
I think I'll still write to CO about it, though I am not actually looking for a refund, since I was entertained.