I'll answer, at least for the 757 side of things. QOL is not very good. You are gone a lot, your base and or contract will change very frequently, and there are a lot of lifers there who will not go anywhere until they shut the doors, so movement is minimal. The contract is a joke, and the union has been in negotiations for quite a while without making any significant progress. Pay is crap, and everytime you switch seats, contract, or equiptment you return to first year pay. I am not quite sure about the 737 or MD80, but that's my take on the 757. My advice is not to go there unless you don't have any other options.