I would surely buy almost any upper before an Aero, don't like their rails either....................JMO
American Defense are usually reasonably priced & seem good on what I've used. BCM is also top shelf as well & are fitted to be very snug on the barrel extension fit...........usually have to heat the upper to get it to slide in easily; this is a good thing for accuracy, IMO.
I just did a build using a V-seven matched upper & lower & their stuff is excellent.
Viltor MUR is also very good, a little heavier wall (stiffer) but also more money.
Many say it just doesn't matter so take your choice, pay your money.
MM
