S@W AR15s are lower end builds using lower end steel in their parts. They look nice but this is the classic buy once and cry once situation. Colt, Bravo Company [BCM] and Daniel Defense are the highest quality ARs you can buy They use the proper "machine gun quality steel". While I don't consider myself the ultimate expert I purchased mt first AR in the early 1970s and have been around them enough to know Quality ARs take a licking and keep on ticking. The lower end bottom feeding ARs will make a fine tacticool range toys. 20 inch vs 16 inch? I would get the 16 inch first . The 20 inch is a real nice shooter though. Really no one owns just 1 AR. M4 carbine .net and ARFCOM is a wonderful resource for learning what makes a high quality AR. Also read this link AR.
http://www.slip2000.com/blog/s-w-a-t...ine-filthy-14/