I have a Fortis Red on my .308 and it works pretty well and I am happy with it.
I have a Surefire Socom comp, VG6 and Voodo Jetcomp, of the three the VG6 is by far the best at reducing muzzle rise, the Jetcomp and Surefire are almost as good and would serve you just as well with just a hair less muzzle rise mitigation .
With that said no muzzle device alone will give you a completely flat shooting AR, if you want a rifle that literally stays flat even while doing mag dumps add an adjustable gas block and nearly any compensater listed in this thread and you will be blown away.
You or anyone that is wanting to shoot one of my ARs you are more than welcomed too, I go to Uwharrie fairly often and could meet you there.