I haven't watched it, but I have to say not having to go to a "real" dealership (and bathing in Lysol afterwards) is a huge plus for me. I've only done it a couple of times, one of which I should have walked out on and the other one was ok, but the wanted to charge me $500 for locking wheel nuts (seriously)
The fixed price model is a huge plus too. Even if you negotiate a good price at a dealership, you'll always question whether you could have done better