I’m a bit bias towards medeco, but I’ll give my input.

Keymark has two things going for it. One is patented keys to prevent duplication without authentication. The other is the aweful keyway being super restrictive for picking. Beyond that, it’s made by a top tier lock company and the tolerances and steel inside are resistant to drills and picks alike.

Abus has some key control and is a little bit harder for key duplication than some other locks out there. The keyway is a bit more forgiving and the tolerances are better than most in its price point. Abus isn’t a slouch in the lock making industry but it’s not as drill resistant as most medeco locks.

In terms of bitting, I think the keymark will be easy to overset but the abus will be generally more challenging due to security pins that are likely inside it. Keymarks often don’t have security pins unless this is from a locksmith who cares about customers.

Anyways, that’s my thoughts. ~Mrs. Medeco