I've sat in the M&T a couple of times. There are some big advantages: the food is terrific (it was good enough to make me regret cooking at tailgate), as is the drinks service (especially if you don't like beer and want other adult beverage options), and if you hate the cold, well, you won't have to worry about that. The bathrooms are nice.
That said, those above who said that they felt cut off from the rest of the crowd, are right. It's a huge disadvantage. I felt like I was watching the game in a sports bar with a really nice view, not like I was at the game.