About a year or two ago, someone at the range asked me about if I had tried the 80% lowers, and at the time, I was leery of them (and him asking) and said "No!". I had no interest in them at the time, and really didn't know much about them. I was actually a little concerned about the legal side of things - my lack of knowledge made me reluctant.
Fast forward to 2021 and I have successfully built one and have ordered a forged 80% from 5D so that I can do another. In the present political climate, it seems to be in my best interest. Plus, it's really fun making things myself.
I suspect that my second one will go even smoother than the first, and it wasn't too bad of a project though I had to dig the trigger well a little deeper with a dremell tool after the fact for proper fitment. My initial milling was not quite to spec, as I got a little nervous about the bottom getting too thin. Learning experience - follow the directions. :)