Double Tap Tactical will get you fitted out if you want the best AR there is available, although at $1.7K for an airsoft AR you could just as easily buy a real steel one.
Other than that brands to look out for are G&P (I own 2), and VFC for electric. If you want gas powered and that little semblance of recoil; WE (will need to gut it and replace with more durable aftermarket parts), KJW (ready out of the box), and KSC/KWA's newest offerings (they're actually quite nice but kind of late to the Gas Blow Back Rifle scene and are competing with companies that have a couple years ahead of them in R&D) are probably what you should look for.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE