I don't think being a Diamond is that big a deal. Time after time in the states, I have to ask for an upgrade, and then many times I'm given the "we gave you a very nice KING size bed" line. In San Fran, I had to go down one tower and up the next to get to the lounge.
Being a Diamond in Europe is where it pays off. They treat you very well and you don't have to ask for anything special.