Really that's subject to opinion and you really can't compare the two given they are two distinct genres. If you like horror, then you'll prefer TWD. Simple, really.
Not at all, in any way. Im a huge horror fan, I have about 1000 DVDs, 90% horror, from all decades.
Romero is my god, not just for his 'dead' films, but also for The Crazies and especially Martin. I was looking forward to The Walking Dead, but it's just dull, the writing is flat.
Mad Men on the other hand, is superb and is up there with The Wire.