Updated a trigger in my current go to gun yesterday. Rise Armament RA-535 Advance Performance 3.5lb. Had it sitting around for some time and finally put it in. For what it's worth...I'm a single stage guy and like a slight curve (not flat) trigger. Bought this one on super sale quite some time ago. Couldn't decide which gun to put it in, but decided my Aero is my favorite for now..
3.5lb pull, VERY little takeup, very short reset. Shot 90 rounds through it afterward; 30 each of PMC .223 55GR, Frontier 5.56 62 Gr, and homemade reloads 62GR w/Russian powder. All fired well.
Man....I like it. Didn't expect a big change in the trigger, but very very crisp. I like the lighter pull and short take-up. Super fast reset...well everyone swears this is super fast...but mostly I'm trying to stay on target.
Also swapped out the Magpul MOE grip to an ERGO grip. I like the ERGO grips. Soft on my girly hands
So this build is AERO M4E1 lower with MOE SL-S stock, PSA upper 16" mid-length, 13.5" lightweight M-lok handguard, Strike Ind. extended CH, Romeo5 Red Dot (plus the MBUS pop ups that came with the upper), Amaspec Stealth Recoil Spring, Toolcraft Nickel Boron BCG
This is my everyday shooter. Like the Red dot very much, and the stealth recoil spring really does quiet down - no twang when firing and also no rattle when carrying or shaking the gun. Also been happy with the Nickel Boron BCG - have that in three guns now. Much faster clean and really easier to see for cleaning.
I have a WITT machine muzzle rise eliminator/brake which I have yet to install, which I also bought on super sale long time ago and read rave reviews on.