Bought one of each. EPArmory standard. Polymer80 blem.
EPArmory didn't need any jigs so I started with that one. Worked out OK. Some voids where there shouldn't be in the pocket. No way in hell you can drill the various hole as well as they need to be. They need a jig for this, their little dimples don't cut it. Safety selector hole is way off due to drill walking. I need to fill with epoxy and try again. Trigger pins were off enough that they had to be wallowed out a little to get the pins in. I should have cleaned the dingle berries better. Something got in the pivot plunger and it is hopelessly stuck in its little hole. All up, I give it a solid C. Not the best but should work. I used a drill press to hog out most of the material before going to the dremel. The plastic is pretty tough. Dulled 2 Dremel 115 cutters cleaning out the pocket. Also used a sanding drum and drywall cutter bit smoothing things up. Drywall cutter worked nice for getting little bits in corners.
Polymer80. This was a blem. I noticed some scuff marks, don't see anything else that stands out. I need to get my mini mill set up before starting this one. I learned from the EP lower that you need a rigid clamping method. There is a lot of force on the cutters and my drill press isn't solid enough to hold things down. No build report yet. This lower seems like they make the most adjustments for being polymer vs. Al. More later.