I have always found the AA 737 F seats much more comfortable compared to DL 737-700 or 737-800 F seats. Not sure pitch is much different but the AA seats are very comfy.

I am not a big fan of the domestic AA 757 and prefer the domestic DL 757. AA's 757 are old and drab and pitch feels the same. Plus I like boarding by 2L on DL which never happens on AA's 757 IME. I do love the new TATL AA 757 F seats. Very nice ride and beats any DL "power" seat I have experienced.

AA doesn't fly the MDs on my routes so I can't compare a recent experience on those.