Not usually much of a difference. I have had one or two that caused problems. The Anderson kits tend to go together easier, and they tumble polish their triggers and hammers. It makes for a noticeably smoother trigger operation. It is still just a military type AR trigger pull, but a better version of it. I have assembled dozens of AR lowers, and there is one or two brands I avoid, and one or two I seek out, but Anderson is at the top of my list.