I was using Arky Armory in Springdale, but I don't like the way he runs things, so I won't be giving him any more money. His Armslist ads are bait and switch just to get you in the store, he never has anything that he says "Just in...." on the ads. He's also using stock photos from Aim Surplus.
I went to Siloam not long ago, probably the shop mentioned above. I liked the guy, and he had a nice store.
I've heard good things about Specialty Arms in Fayetteville as well. I've never used them, but my friend down there uses him a lot and has never complained.