Like a significant minority of users, I've replaced the pads on my Sony headphones (the MDR-7506 in my case) with these Beyer pads. The fit is good enough to work, and durability is at least as good as the stock pads.
A couple of caveats, however:
1. There?s a bit of a bass bump with the Beyer pads on the MDR-7506. You may or may not like the resulting sound. Possibly more significantly, the Beyer pads tranfer the cable vibrations to your ear more than the stock Sony pads. If you use your headphones in outdoor/location settings (on the move, in the wind), the extra cable noise may be an issue.
2. The material is different from the stock Sony pads, and you might find them less comfortable when working in warmer and/or more humid environments.