On my 300 PRC I've tried:
- APA Gen 2 Lil Bastard
- APA Gen 3 Lil Bastard
- Hellfire Match
- Terminator T3 (current)
All felt similar, here's the ins and outs of each:
APA Gen 2 Lil Bastard:
- Good brake, solid recoil reduction without being massive
- Easy to take off
- Less easy to time due to it creeping when tightening the locking nut
- Loud
APA Gen 3 Lil Bastard:
- Same as Gen 2, but slightly better at not creeping
- Gave this to a friend of mine who got a 300 PRC
Hellfire Match
- Similar recoil reduction to the APA and also loud
- Easier to time (no creep), but harder to take off and clean. This was the deal killer for me. It has been relegated to my 308 wind practice rifle.
Terminator T3
- Excellent brake with great recoil reduction.
- Seems less loud, but it could just be my hearing going
- Far, far, far easier to take off and clean (it is not self timing)
- The main "negative" is that must be timed to the barrel when cutting it. This adds cost, but something I gladly pay to get back the ease of removal and reinstallation (not to mention consistency of placement).
They all have their pros and cons. If you don't mind having your barrel timed for the brake, the Terminator brakes are the bomb (I also have one on my 37XC - a T5). If you must go self-timed, my recommendation would be one APA brakes (Lil Bastard or Fat Bastard - either is fine) in stainless steel (for ease of cleaning using chemicals that would otherwise kill the finish on the black ones). Additionally, APA now has this gizmo called the Cone of Shame, which creates a small sound block heading back toward the shooter. I bought one to try it on my 6mm, and it does reduce sound.