All pre-panic of course...
For the most part, anything under $1K is going to be okay for a plinker and some are better buys with better reliability than others. In the low end group, I have seen enough of the Windhams and S&Ws to beleive that they are good quality and my choice in the low end. The Del-Tons seem to be decent, but I have not handled enough. As you tip over that $1K mark, then the Colts, DD, BCMs, Stags, Rock River, POF, LMTs are all quality ARs and you are really picking the company and or features you like the most. When you start to pass $1500, now you are really looking at specific features and or purposes and the reliabilty, accuracy, fit and finish become more expensive as well. Some of those that cost more than $1500 are really not worth the scratch. But, you are also looking at divergent capabilites. This group includes companies like Compass Lake, JPRifles, Noveske, LaRue, STI, Les Baer. However, Colt, Stag and Smith and Wesson also have task specific ARs that can get into this group. Many in this group are in the $2000 to $3000 range. BUT, there are less than optimum parts on many of the top tier stuff because their competitor makes a better part. Billet receivers are for adding weight and looks, but add no performance at all. The BCGs from Youngs and JPRifles are the best, so in most cases you are going to have to wait for a JP, get one custom built on spec'd parts or build it yourself.
Using top quaulity parts, I've built uppers for customers that range from $800 to $1700 to fit their specific requirements. Lowers are actually simple to build and most of the best triggers are not only perosnal preference, but simple drop-ins. We end up having customer rifles that out-perform most of the top tier stuff with a much lower price tag when they build up their own lowers.