I would put PSA and AERO neck and neck as the top on that list. Did not know S&W sold their lowers separately, I have heard of Bear Creek but never used, Polymer 80 depending on the application may be OK
Of your choices...
Aero.... probably better of all your choices
PSA.... Nodak Spud ( retro lowers ) NS first then PSA
Smith.... no experience
BCA... a lower is a lower
Poly.... don't do Poly..
Then you have...
Anderson.
Bkingsfirearms
Gorilla Maching
to name some..
you can get lowers in different forms, metals, etc. Your wallet / credit is your guide.
got lowers from various places even Sendra, they all work, no issues / no problems
even some of the "blem" lowers which go cheap, only thing I've found is the anodizing, everything else is ok.
¹Better...? Define better. (Not trying to be snart) sometimes better is "not" better
I used a poly. This was back a bit and when I saw the cost I thought let’s try it. I have used it as a lower for 300 BO upper. i have no issues with it. Haven’t shot it much. Bit there are caveats:
- because its polymer, its necessarily thicker so pushing the take down pins out is a PITA;
- the hammer and trigger pins are held in allen screws on both ends of each pin. For as much as I shot the carbine its okay. I would not consider it for anything but occasional range use. I did read on some failures, don’t recall where…I think the buffer tube boss cracking…but don’t quote me on that.
I like SOLGW - Sons of Liberty - you can get cosmetic blems from Big Tex Ordnance for a reasonable price. Dimensions are very good. And the anodizing is awesome.
Cheap bottom-tier makers like BCA, PSA and Anderson can make a decent lower but seem to have no QC program at all. It's a complete crapshoot whether you get a good one. And the replacement they send you might be just as bad. Considering that the lower is serialized, and will have an FFL transfer fee, I'd rather buy from a company that has a better reputation.