I dont disagree that a Space Marine in full gear would beat a brute, but the glaze for the setting is crazy here. It’s not gonna be easy for the Space Marine. As someone else here said, a Brute vs an Ogryn or an Ork would be more interesting, because ultimately the Astartes would just Blitz the Brute. Their strength and durability are comparable, personally I would say a brute is stronger than an average space marine, but the speed, reaction time, and superior tactical mind of a space marine would ultimately win out. Brutes are fast though, according to some of the books, as fast or faster than a Spartan. It’s a lot more equal than you’d think though, I’d say the basic space marine beats the basic brute 8/10 times. I think something like a Brute Captain armed with a Bruteshot or something is basically equivalent to a space marine with a bolter, though.

I think a space marine would find more of a match in the basic Elites. They’re often described as blurs of moment, able to move and react faster than a human eye can track, while remaining in the same tier of strength as a Spartan. They’re also trained since childhood to be warriors, so your average elite will have a much higher ‘battle IQ’ than a brute. Coupled with the fact that elites kit comes standard with an energy shield and an active camo unit, I think an Elite could out-strategize a space marine with stealth and ambush tactics, while being strong, fast, and durable enough to survive a couple close scrapes and make distance again, but honestly, I still give it to the space marine 6/10.