What is the best way to decide between stripped lowers? I am not sure if there is any more functionality between these or is just the way they are made, but which
one would you go with? i am torn between these guys.

Larue Tactical Stealth Lower

Noveke Forged Lower

Noveske Billet Lower

Mega Arms Billet lower

This is the one you want.

why the PSA receiver?? I do not really know very much about them?

Price.. They were on sale for 50$ not long ago, vs. the couple hundred you're looking at for the previously mentioned models.

You can find any number of nice lowers for 60-80$. Only difference really is the roll mark (logo.) Unless you go up to billet, then you may have some additional strength.

I personally would go with a forged lower rather than billet. I would go with a AXTS A-DAC lower since you can use a 45 degree safety and has bolt lock incorporated in the mag release.

LINK

Why? It is a well-made receiver that sells regularly for $79 and can often be found on sale for $49. I have built eight rifles using their lower receivers as well as their LPKs and every one of them shoots as good or better than my Bushmaster or Colt.

PSA is a relative new-comer to the AR market but they are gaining steam by the day.

i like the JD Machine  striped lowers myself...  just becuase they make thier lowers with a flared out magizine well, and that makes it a little faster on the mag change for anytype of dynamic type shooting...!!!

other than that i also like the LRB's very well made and also very well priced...  

I choose these 2 recievers to build off of becuase of price and quality... booth i can get under 100.00 with transfew included...!!!   dont get me wrong i wouldnt mind having a nice Noveski Lower but i would NOT buy one... for the money, i would rather just have a JD Machine...!!! or a LRB for my second choice..!!!

Thats JMO

It's mostly cosmetically what you want.
Billet's look more modern, but functionally are the same.
The forged are just as strong, or even stronger than the billet due to the high pressures used in forging the blank, then heat treating to lign up the molecules.
Just stay away from cast lowers.  CAST IS JUNK!  They are inferior in strength to billet and forged.
As far as forgings go, there are only a couple of companies in the U.S. that produce raw forgings to all of the AR manufacturers.
I know this for a fact.  It's all about the accuracy of the machining of the manufacturer after that.  The CNC ops programs are sold to manufacturers so most of them are the same.  SOme may tweek the program a bit to make them unique to others, or to add ambi controls.
Most mag wells are EDM cut for smoothness, but other s have worked out the broaching which is cheaper.

All depends on what you want to do. Most lowers are GTG now. A $79 PSA is as good as a $179 Noveske.  What upper will you be using. If a Noveske upper use a Noveske lower. Not because any other will not do but the resale will be better if you have to sell. There's no benefit to a billet lower there just looks.

flip a coin

Any of the four on your list are fine. Go with what your budget allows and pick one.

Tonight I just assembled my first lower using a PSA lower and parts kit....it went together so easy I thought I missed half the steps....awesome finish on t he lower...fantastic customer service...you will be happy with a PSA.

I've not built the number of guns a lot of guys on here have, but will say I've built Noveske, PSA and Rock River...and the extra lowers I have squirreled away are PSAs.  Buy what you want...I got the Noveske because I didn't have one and was building an SBR that I'll have a lifetime and it was what I wanted.  There are no bad lowers out there (except have heard some bad things about Blackthorn) so I buy price and roll mark.  If a 200+ billet makes u happy, go for it.  Just knwo there's no quality difference I can perceive. I personally love the PSA crossed cannon roll mark and for 49 bucks on sale I keep several around and just don't look elsewhere.  I buy one or two when PSA runs them on sale whether I need them or not and try to keep one in reserve for each of my children and grandchildren as a Second Amendment gift just in case I putt out on 18 early...

My personal favorite is CMMG.  Very nice deep black finish, low shelf and good quality.  Honestly, there isn't a lot of difference between any of them.  Mostly, you are paying for a brand name and a roll mark.