One of the main things to consider when taking advice or opinions on ARs (and any other gear) is the experience of the person giving the recommendation. Many people will tell you I have X brand AR and it has been 100% reliable. That sounds well and good at first brush. However, it is a pretty meaningless statement. 100%, to use an extreme, example could mean they have fired 1 round and it went bang. I've often found that if I ask a few more questions, some of these folks are in fact referring to guns that they have merely fired a few hundred rounds from. Furthermore, these statements typically provide no context for the conditions of use. Even thousands of rounds tells us very little if they were slow fired round, maybe 25 or so in a range trip and a good cleaning and oiling between each trip. X brand may run like a top when subjected to such use. Screw a suppressor on it and run it through a three day 1500 round carbine course and the warts might start to show. Shoot a years worth of three gun and it might be a different story.
You may not intend to shoot suppressed, or shoot a couple thousand rounds in a weekend, or use the rifle for defense and that is fine. However, it is nice to know what a recommendation is based on. In my humble opinion someone shooting a few hundred rounds casually on a square range under ideal conditions says nothing about a gun.
A further problem is that many people simply don't have experience with a large enough sampling of guns to give very meaningful input. This is why I tend to value the opinions of those that see a lot of guns and a lot of rounds fired every year under varying conditions. These people include competitive shooters, carbine course instructors, and even some individuals that get out and shoot a lot. An example, Travis Haley at one point stated that he shoots around 100,000 rounds a year. In addition he probably teaches about ten open carbine courses a year (he likely does more training for others as well). These class tend to have 25-30 students I'd imagine based on my experience. They are typically 1200 round classes. That's about 36,000 rounds fired during the class by students. That's 360,000 rounds over ten classes taught. In sum, that is a guy who probably sees north of 500,000 rounds fired a year through hundred of different guns, in semi trying conditions, by lots of different people. He has been doing that for a lot of years now. That is an opinion that is slightly more informed and meaningful than, my brand x has been 100%. The same is true for guys like Pat Rogers, Larry Vickers, Costa, etc, etc. If you ask these guys they will tell you that some brands consistently fair better in terms of reliability and durability in their classes, particularly when guns have suppressors. Certain brands have earned their reputations. It really is not simply that folks want to spend more, or buy cool guy gear.
To my mind their is simply not enough price difference between well proven brands that do not cut corners in the manufacturing and assembly process and the others to worry about buying a lesser gun. Over the life time of a gun, what is a couple hundred dollars?
When you list defense as an intended role it will change what many people will consider an advisable gun. This is true of both brands and configurations.
As to my recommendations I agree with the above advice to do some reading at M4Carbine.net. There are many very knowledgeable posters. it can also give you some context for, and additional information about, the spreadsheet linked to above. Those things make it a more useful tool IMHO.
When I recommend guns to friends and family as well as buy for myself I stick to the following brands:
Noveske
BCM
LaRue
Colt
Daniel Defense
Not all of these offer the same "value" IMHO, but they are all pretty well proven guns. For a general use gun you are unlikely to regret buying a gun from any of them. You ask for an "average quality" gun. Their are so many makers of ARs it is hard to quantify what average quality is. However, to me it would be a basic mil spec gun. Some guns, for example offerings from LaRue and Noveske, are not mil spec but IMHO exceed mil spec guns in certain respects. To put it another way to me Mil spec is a floor for a defense gun. It is not a ceiling and it can and is exceeded by some makers in certain respects. Your average comments make me thing that something like a basic colt or BCM is probably more up your alley than a LaRue, KAC, or Noveske in terms of price. Which I pick among the listed brand really depends on, price, specific intended uses and preferences (for example if accuracy was my biggest concern with longer distance shooting being a main use I'd get a LaRue). These days I typically buy Noveskes.
I also have one PSA gun. Given the price ($600) it was too good to pass. I think PSA is a brand that is building a good reputation but is not as proven as some of the others. I will say given the very limited use, around 1K arounds in a few outings, I've put through the PSA I've been happy thus far. PSA is my recommendation when price is someones number one criteria. However, the price of PSA guns have been creeping upwards along with their blossoming reputation. They have of course had some hiccups but their response and correction of those teething problems seemed to be appropriate from what I saw.