Everyone will have their own opinion. Each one is just as valuable as the next, since they are all totally subjective. Having said that; here is my own, totally subjective endorsement. I own two AR type rifles, One is a Bushmaster ORC (Optical Ready Carbine) and I am really happy with it. The price on the ad you showed is pretty good, so, if you want to give one a try, you won't be sorry.
ARs are like Harleys, IMHO. Nobody who owns one leaves it stock! You will end up tweaking the sights, stock, sling, rails, handgrip, etc. Have fun and don't spend so much on it that you can't afford to buy a good lower and build your own for the next one! You can't eat just one AR!