This is a very lightweight, beautiful matched set. As part of my first 80% build, I wanted to go with a billet set that I thought had all of the features that I wanted in a non-80% like a mega arms ar Santan Tactical. While I think some details were missed, I still think this is a nice set. I liked the milling, overall shape, and ambi-bolt release, the hardcoat anodize, and how tight the receivers seemed to match up. Here's what I did not like… no clear instructions on how to assemble the custom hardware into the lower receiver. There are a few new pieces not found in the standard mill spec parts kit. It's not terribly difficult to figure it out, but it would help to have some written instructions. Another lesson is to thoroughly wash with soap and water the lower receiver once you're finished milling it. This is to remove any small metal shavings that could be hiding in the various hardware holes on the threads. I had a hard time threading a couple of the pieces and it was due to small metal shavings. The jig is a very high-quality, with the exception that I found the safety selector hole to be too small for the drillbit. The holes in the jig are reinforced with steel insert, in that steel insert would not except the 1/8 in bit. Instead I drilled a hole with a smaller bit, and then went back through with the 1/4in endmill. This isn't ideal, because I find the hole to be just a little big, maybe by a couple thousandths. I also found that the receiver would not except the standard length buffer tube retainer spring and retainer. When I try to insert the retainer in spring together, it would to get hung up on metal in the hole. Upon inspection and cleaning, it appears to be a manufacturing error. I had to take the retainer to a bench grinder in order to significantly reduce its overall length. I also clicked the spring to a sufficient length and was able to get the assembly into the hole so that I can install the buffer and spring. The result is that I find a little bit of binding when I close the two receivers together. It seems to me that the bolt needs to navigate on top of that buffer retainer in order to fully close the receivers together. I also found that the holes for the takedown pins is a little big for standard mill spec pins. They fit a little loose. This set also has a screw that presses against the upper receiver take downhole in order to create that super tight fit, if desired. I would likely buy this set again, but I would probably do the build a little differently. If I had found the quality issue during the build, I also probably would've contacted JL directly to see if they were aware of these quality issues. If you also do this bill that I highly recommend a router that has a plunge feature, instead of freehand. This allows you to slowly insert the end mill in properly control depth.