In a K1 fight, Mousasi takes it 100/100. In a BJJ match, probably 85/100. In an MMA fight... I'd say Jones by decision 100/100 (right now).
I don't think Jones would do any damage at all to Moose, but he'd definitely win in an MMA fight. Mousasi looked great against OSP in terms of wrestling improvement, but we'll see if he's still training that hard. The guy is an absolute stud but trains by fooling around a few times a week.
sig credit to Limba