If I'm hungry and want a real meal, I go to the Amex lounge - also depends on how busy the MLL is - it's nice to just step out of security and walk 4 feet to the amex lounge if I'm in a super rush.

If I want a good selection of liquor to relax for the flight I pick the MLL.

If I'm travelling with my wife and child - Amex wins hands down - less people, less stares when my daughter walks in (yes, she's the 27 month old who flies just as much as the rest of you and sits patiently making less noise than some of you grumps). If I took her to the MLL, I'd be worried about lounge rage from FF's.