I am getting close to building an AR & I am still checking prices. I am wondering what is the best $400 Dollar Complete AR 15 Upper, chambered in 5.56-223. A couple of features I must have are *A3 or A4...........I already had an A2 upper & I would rather have a flattop. *Dust cover & forward assist A couple places I see uppers R GUNS......I've never heard of them...but 440 for a 16" with a free float sounds nice DS ARMS.....They make good Fal's Del Ton *** I am thinking about going with them, but, how long is the waiting?? Model 1 Sales....I have heard they have good prices My other question is, Should I go carbine or mid length? What is the difference between the two? 16" or 20"??? On some of these uppers you can add $50 and get a SS barrel or a SS BCG. Is that worth getting?