I'm not impressed with PSA's abilities in building uppers.
Mine came with finger-tight freefloat rail attachment screws and the rail was improperly installed. Thankfully, I checked the screws for proper torque. I also found that the low profile gas block set screws were only finger-tight and that the barrel was not dimpled prior to installation. There was also no threadlocker of any sort on the gas block screws. Considering the ~30,000 PSI of port pressure, I expected a little more attention to detail on the gas block installation.
It'll be harder for PSA to mess up a basic upper, but I would expect an upper that still needs a good "once over" before running it through its paces. A half-done parts kit upper, if you will. In my case, second-guessing PSA turned up some very poor assembly methods and my corrections were required to make it right.
Since this is your first AR and you might not have all the tools or know-how to correct a poor assembly job, I would suggest buying a complete BCM, DD or Spikes upper and a good BCG from either of them.
If an M4 configuration is the goal, then a Walmart Colt 6920 really is the best answer in the long run.