Armaegis was talking about using the Shure 840 pads on the M50. The 840 pads are very soft - one of the most comfortable I've used.
Comparing the A700 directly with the Shure 840 (comparing the two cans) - the A700 is definitely more comfortable because of it's design. SQ wise, I much preferred the Shures. And FTR I found the Shures supremely comfortable - just a little heavy. The problem is that with the 840's most people either love or hate the comfort. You're best to try them first if you are considering the 840's.
Do you know any good stores on either Boston or New York?
I'm probably traveling there next year, so it would be a good oportunity to try and possibly buy some cans