I shoot one extensively. I don't miss the FA or lack of dust cover, for my shooting with that particular rifle hasn't require either. (knock on wood) I have others I'd grab in must-fire situations, so lacking a FA or dust cover is just not an issue to me for this rifle.
Good quality and I'd buy another, etc.
However, I wouldn't recommend it for left-handed firing even though I have never tried it with this rifle.
The ejecting empties bounce off of the upper behind the ejection port for several inches (you can see the marks from the case mouthes in the right light after who-knows-how-man rounds)
Also, the brass ejects right and rear, but a little more rear than my A2's and A3's.
Depending on how close on the stock for your cheek weld you normally shoot, that could bring the hot-empties "very close" -- not my idea of fun shooting.
Cheers, Otto
ETA: its not exactly "building your own" if you buy a complete upper that you like for a good price and push together 2 pins on a complete lower. It can be cheaper too: no sales tax on the upper, infinite internet order-able configurations shipped right to your door, and no FET on just a complete lower purchased for a good price from a local dealer.