You'll get a dozen different brand names thrown at you. A lot of it depends on how 'milspec' you want the thing, if that matters to you.
I finally decided to get an AR after getting frustrated with my AK conversion. Poring over countless threads about this brand and that brand, it occurred to me that a list of things important to me would be helpful when considering a purchase.
I suggest you do the same.
Carbine or mid length gas system?
Target, hunting, paper punching, plinking, home defense?
5.56, 6.5, 6.8 etc?
Nice thing about 'civilian' AR's is the broader range of configurations compared to the M4 you carried.