Opinion has nothing to do with a canonical battle with both in their primes.
Malgus was a dominant force user who faced off against the best champions the Empire had and was only beaten when he was knocked down a reactor shaft.
He achieved oneness with the Dark Side of the Force, he was so powerful that Satele Shan was scared to face him ever again, the same woman who was the much more powerful descendant of Revan and Bastila mind you, she could take out Harrower-class Dreadnoughts, could use tutaminis on whim, had visions and precognition never seen before, a battle meditation that could span an entire sector and much more.
Malgus was completely focused on his goals and did not have any of the arrogance or fool-hardiness of other Sith, you know the really scary thought of what the Sith could be if they didn't riddle themselves with infighting? that's Darth Malgus.
He wasn't just praised by the Empire though, Darth Sidious himself praised Darth Malgus as one of the greatest Sith combatants on record and told Vader that he should model himself after him, not Bane or any of the others like Vader, but Malgus.
That's why you're the defender of canon. I never knew any of that (except for the part about Sidious and Vader). And I completely agree with you as I have always done.
You cannot base your debate off of opinions. Only facts. Lesson of the day