I am looking for advise on which model AR-15 to purchase. I recently attended a gun show and looked at Colt, Bushmaster, Olympic, etc and since I am only familiar with Winchester Model 12 & 42 shotguns, I thought this would be a great place to solicit advise. Do I want pre-ban or post-ban? Does manufacturer affect future value? What features should I definitely get?  Any help is appreciated.

If you want an investment get a preban Bushy or Colt
If you are going to shoot it doesn't matter.
I do like chrome lined barrels.
cpermd

Colt, Bushy, or Oly. Get one with A2 sights 20 inch 1 in 9 or 1 in 10 twist heavy barrel. If you want to use and abuse it go post ban. Otherwise for general usage with TLC go pre ban.

Bushmaster, Armalite, Colt all make decent rifles. I think you might want to stick to Bushmaster. Olympic Arms doesn't have as nice of a finish. But Olympic Arms does make some very accurate barrels.

You might want to consider getting an A3 model (removable carry handle): 20 inch barrel.

BUSHMASTER