In my opinion, the majority of folks would be very happy with the RRA. They make a very solid middle of the hierarchy rifle and it's been my experience they stand behind their product with good support. I have a RRA (5.56) that I often take to carbine classes and as long as I use good mags, it's never skipped a beat. Keep in mind most of those classes are 800-1,200 rounds in two days...without cleaning.
The colts, in my opinion, are a better rifle. The bolt carrier is of heavier construction, the gas key is properly staked, it's been high pressure tested, and many other things to help improve the reliability of the weapon.
But if you are not going to be running the rifle hard, or ultra-reliability isn't required, it's questionable you need those improvements...now if you can get it for the same price, why not
Which weapon you choose has a lot to do with what you plan to use it for. Safe Queens just have to look good, they don't have to be reliable or accurate.
Typically, a varmint rifle needs to be very accurate and can give up some on the reliability...longer barrel, better trigger group, improved chambers, etc.
But for a home defensive weapon, reliability reigns supreme. It needs to go bang every time you pull the trigger. It doesn't have to be able to fire 1k rounds at a single outing, but it may have to fire a mag or two without a failure. Generally, it will have a shorter barrel then the varmint and a collapsible stock (more maneuverable in the confines of a house). 3 MOA wouldn't be a problem since most shots are at relatively close range (for a rifle). Rail mounts for things like red dot sights and flashlights/lasers are typically included in the build.
If you are concerned about the Zombie Apocalypse, then ultra reliability trumps everything else. It needs to be able to put out thousands of rounds without a hiccup
No matter whether you buy mid or top end, it's been my experience the mags are the number one determiner of reliability. This is one area not to get cheap on. Buy good reliable mags with the proper followers and you will be a lot happier with your rifle. Buy cheap and you maximize your chances of experiencing Failure To Feed, Double Feed, bolt not locking back on last round, mag not dropping free, etc.
By the way, I have two Zombie Apocalypse rifles, one is RRA and the other is a Colt. The Colt is well past 10,000 rounds and the RRA is approaching 10,000. Other than regular maintenance and periodic cleaning, I have not had to do anything to either to keep it running.