Have found rough or out of spec stuff with Anderson and DPMS, Aero without grip and FCG is my go-to, local gun shop stocks CMMG parts, and I'll use them if I need individual parts, never a problem with those two brands
What have you found out of spec with Anderson lowers? I have one lower and 2 uppers that I took to Chad's Armorers course and we found no issues, I have 5 more builds on Anderson lowers and all but one with Anderson uppers, that I have never had any issues with.