I'm looking at getting my first AR-15, and I know at this point I want it in 5.56/.223 and I'm pretty set on a 16" barrel and I want a gas piston system. The other thing is I will be highly customizing it. So it needs a flat top for sights like an A3 upper. My budget is around $1000 and I have no clue on a brand. I have found that the brand image seams to really be effecting my decision as well. I don't want colt because of the horse and I do like Bushmaster because of the snake, but I've heard bushys arnt very good rifles. Any suggestions?