suppessor or muzzle brake

which reduces recoil the most effective?

No question muzzle brake. I think the one comparison I saw showed somewhere around 30% reduction from Suppressor and mid 60% from Good brake. I am sure there are brakes that don’t work as well as a Suppressor and I have noticed the Brakes that allow Suppressor to be quick attached are not as efficient as some of the good Brake designs.

My harvester suppressor has a brake on the end of it. So I say suppressor.

Brake

Both together

I shot a 28 Nosler with that exact Suppressor on it about two weeks ago. The recoil reduction made it tolerable to shoot but doesn’t even come close to the reduction of say my JP Terminator brake that’s on my 28 Nosler.
I can watch impacts on steel at distance with the scope on highest magnification with the brake but with the Harvester I would have to move the rifle back into position to even find the target.
Again there are definitely some crappy brakes out there that are not well designed that probably don’t do any better than a Suppressor but a good brake vs a good Suppressor.... brake wins every time. That’s one reason why you don’t see as many Suppressors being run by PRS / 3 Gun Competitors as brakes.