I first saw the Battle Comp at an EAG Tactical class in SC about two years ago. I'm generally not a fan of compensators on work guns because I don't see that the benefits equal or outweigh the costs. I'm primarily running SBRs and working indoors or out of vehicles so concussion is an issue, if not for me then for my teammates.
After reading several AARs and reviews I decided to give the Battle Comp a try. The Battle Comp was intriguing to me because there were several mentions in AARs about the Battle Comp having little or no increased flash and little increased concussion when compared to an A2 birdcage. I went with a Battle Comp 2.0 because our issue cans are the Gemtech HALO.
I ran the 2.0 for about 6 months. Primarily shooting X135 but some M855 and Mk262 Mod1 was used as well.
The first trip to the range proved that the reviewers were WAY off when comparing the flash hiding properties of the battle comp to the A2. I was Shooting next to men with rifles that were the same length and there was a noticeable difference in flash between my rifle and theirs. There was also enough concussion that the shooters to my left and right commented on it. I fired the weapon from a vehicle ONE time and decided that was a bad plan. Even with foamies and peltors it sucked. The only high point was running a magazine through the gun on full auto. There was definitely less muzzle rise then with an A2. For me this isn't really a selling point because I've NEVER flipped my gun to auto in a fight. Not one time. So I don't care much how the gun is affected on auto.
One thing I did notice is that the battle comp changes the recoil impulse of the gun enough that someone who isn't used to it may well end up pulling follow on shots low. While normal recoil on an AR is a slight push with muzzle rise to about the 1:30, the recoil impulse with a battle comp is very little push but a sharp barrel movement to the 3 o'clock. It's something to pay attention to if you're trying to control the muzzle on fast follow up shots.
Overall I was unimpressed and have since switched back to an A2. I think there are better choices out there if you're looking for a comp.