Thread:LOTRMod/@comment-25793832-20160206172740/@comment-26347028-20160209005701

Dark Lord Mairon wrote: Mightiest in terms of arm, best with weapons. Sauron was the greatest in general, in power and all others, thats why Melkor wanted him so bad, and thats why he trusted angband to him.

Maiar on physical forms werent so strong, and could be killed, any could, Eonwe could too, but he was better at combat.

In general Tolkien says he was indeed the most powerful, just as Grievous said. We dont get to see many maiar fight on first age, so we cant say if they were any better But when one is stated to be the best at arms, and leads the hosts of the Valar, it is reasonable to say that he is a far better fighter than any.