Stripped Upper- AR 15- what to look for, avoid, etc.

I have purchased the tools and was wondering what i should be looking for in a stripped upper? Obviously, there are differences in looks with the billet vs forged. I am most likely going to stick with a forged because of cost, unless there is a good reason not to. Are there any manufacturers to avoid? I was thinking of going with a blemished BCM that they have discounted, but wanted opinions.

From what I understand about stripped forged lowers, they are only manufactured by a few factories, and then distributed. Is that similar with uppers?

Yes, there are few actual manufacturers of forged uppers.

I like billett, so I used a JBO Spartan on my last build.