Vos Legends story is way better than the Canon stuff but I still like it. In Canon, he defeated Ventress, and contended with Dooku, so in any case, he is not bad, but Malgus is superior in all aspects: force use, sabre skills and probably physics too. Vos and Malgus fight would resemble Malgus and Ven Zallow's fight in the "Decieved" trailer, so Malgus would take Zallow down quite handily.
Malgus takes 9/10