Top is an Aero M4E1 best bang for the buck great fit and finish and a bonus of an integrated trigger guard, flared magwell, threaded bolt pin, tension screw under the rear push pin to take any wobble out of a loose fitting upper, no problems with any type of mags dropping free. the Magpul MOE works but it’s sloppy and loose on the buttstock, the grip works fine very basic has more of an AK grip angle and feel.
Middle is an Anderson AM15, people will dog you about it, I got it for dirt cheap during a grand opening sale around $39 or so. It works nothing fancy, open trigger area, roll pin for the bolt catch lever needs to be tapped in with a punch, and everything aligns, some Magpul mags didn’t drop free when new, took some breaking in, other mags dropped free. The Daniel Defense furniture is my favorite it’s rubberized and overmolded, the buttstock is snug, no wiggle, and the grip is spot on without a beaver tail so you can get in good and tight and the web of your hand fits perfectly inline with a more vertical 1911 like grip angle.
The bottom is a Juggernaut Tactical, it’s a billet lower vs the other two which are forged. Nice sharp angles, laser etched graphics, integrated trigger guard, adjustable tension screw to tighten a loose upper, an ambidextrous bolt catch release, angled/cut magwell swaps and drops all mags and a threaded bolt pin. Mission First Tactical minimalist stock real deal made in USA fits nice and snug, Magpul K2 pistol grip has an improved texture, grip mold/angle and a beaver tail.
My son runs an Aero Gen 2 which is very much like a milspec open trigger lower with a tap in roll pin I believe but does have a tension screw.
Of these I really like the Aero M4E1 it is truly a great value as it has billet style fit and finish even though it’s forged and the threaded bolt pin is really nice. I can basically buy about 2 or 3 depending if I find a sale on these for the price of 1 or 2 Juggernauts.
That’s my take on lowers and furniture, the Geissele drop ins are nice, as far as the stocks that’s a reference for rifles. I think that braces would work best for a pistol vs a blade, tube only, or a PDW retractable.