There's really not much kick in 5.56.
What caliber are you talking about?
I'm fond of the VG2 Gammas for the cost. They have a side blast cover you can also buy if side concussion is a concern....however, that bumps the price into Battle Comp territory and at that point, if side blast is your concern, you probably should just go that route....assuming you want a short, A2ish size comp and only need a 1/2-28 thread pitch.
That's the nice thing about the VG2 for .300 blk...it's 5/8-24 and the same size as an A2....so you're adding minimal length but still getting good brake/comp performance.
You're asking "compensator or brake".....most do both. Brakes are the baffles, comps are the top ports. Most designs have both.
What are you looking to spend too? The 2 port brake from Armalite are only like $30 and work very well....though I did drill two ports in the top to get some compensation. Battle Comps are easily $125+. VG6s can go for $40 on sale for the 5.56 to $65ish for the .300 blk. The BCM brake also works pretty well and has less side blast than traditional brakes....about $80; same with Griffin Armament's Hammer Comps.