Condor and Ar500 are not US made, Shellback is.
Unpopular opinion here, but condor carriers can be found for cheap and are "good enough", granted they won't be up to quality with carriers 4X the price i think they are a good bang for 50-60$, not for 100 or more. I saw more pics of it worn by soldiers than i can remember, including atleast some of Swat guys. BTW, i don't use them, i have higher quality items, but this doesn't detract from the fact that oversea made item MAY sometime be good (Tasmanian Tiger, Warrior are very popular and good brands here in Europe).
Another unpopular opinion, it looks to me that the Slickster doesn't offer that many features for that pricetag, i'd buy other US brands like Mayflower. Same for T-rex ARms one, looks to me like that pricetag is due to they being popular and publicized items.
This is a Nice reading on what is good quality, written by respected tactical gear maker Darin Talbot (Extreme Gear Labs, EGL). https://primaryandsecondary.com/what-is-quality/
I would advise against buying something with "alot of molle webbing": i would start by planning your needs then trying to search for something that realisticaly fits them. The ar500 testudo is a very common pattern of plate carriers, with molle front, back, cummerbund and a closure flap. Look at mayflower, or Tactical Assault Gear or Shellback tactical for similar items.