I have these installed on a couple of firearms in order to switch my suppressor back and forth between them. As muzzle brakes go, would this one actually do much, and given that it's under a suppressor, does that limit any effect it could have on muzzle rise and recoil?

Yes, they work for recoil I'm not sure they do a lot for muzzle rise in that configuration. They are louder and a lot more obnoxious than a radial brake. In that picture...the ports are in the incorrect direction...the point of those ports are to direct gas to the sides not top and bottom...as you have it pictured it would blow dirt/dust/sand all over you.

My understanding has always been that's exactly what a muzzle break is supposed to do in order to reduce recoil. With the ports angled back towards the shooter, the exploding gases pull the gun away from the shooter, thereby reducing recoil. It also explains why muzzle breaks increase the sound of the shot significantly to anyone behind the muzzle.

You're talking a different axis.

Judd is saying in the picture the ports are at 12 and 6 o'clock. When installed they would be at 3 and 9 o'clock.

Unless I'm mistaken, that's a SilencerCo break/mount for a Specwar suppressor. They work fabulously well under the suppressor; once mounted, I've never shot any of them without the suppressor unit. I've got similar setups for both Silencerco and Griffin Armament units and they're both great. My .338 LM feels like a .308 with this setup, and anything .308 down feels like a .223.

^^^^This, sorry I didn't word that quite right.

You wrote, what you wrote correctly. It was misinterpreted.

The brake will not have any impact on muzzle rise or recoil when it is under a suppressor. If you take the suppressor off the rifle and shoot unsuppressed, then the brake will do its thing. The advantage of a brake vs flashhider for QD suppressor attachment is that the brake serves as a sacrificial baffle of sorts.This can extend the life of the suppressor's blast baffle, especially on a SBR.

Think of it logically. Brakes work by controlling where the gasses go as they exit the end of the barrel. When a suppressor is attached, the gasses are "blocked" from exiting the sides of the brake by the suppressor and must go out the end of the can instead.

Suppressors reduce felt recoil, so you will feel a reduction in recoil when shooting suppressed vs. unsuppressed, but whether there is a flash hider or muzzle brake under the can doesn't change the felt recoil when shooting suppressed.

The choice of flashhider vs. brake really comes down to what kind of muzzle device you want on the gun when it is unsuppressed.