I've owned a PJ and been around Big Tex and Kaufman's. I'd own either of them but I do think there are differences in quality (and reflected in price point).
In my opinion, we see a lot Kaufman's in our area due to the fact that they're manufactured here in NC (not far from URE in Silver Valley...Lexington address if I'm not mistaken). To me, they're a good "value" trailer and I consider them close to the bottom of the "quality" spectrum that I would personally go (thinking the likes of Mid-State trailer, etc....I personally would NOT own one of their trailers and just pony up a little more cash to have a better trailer than MST).
@Chris_Keziah has a 20ft 14k equipment Kaufman and it seems to hold up well unless
@Hoodw!nk borrows the dang thing. They appear to be built fairly decent but lack some of the extras that I'd want in a trailer. That being said, that's not to say I wouldn't buy one new from them whatsoever. I do like their DTC model so I don't have to deal w/ middle man mark-ups (it'd be easy for me to call them, order what I want, drive down in [[insert number of week backlog]] weeks and pick it up).
I think BigTex and PJs are next level, personally (and BT nudges out a PJ but not by much). They're both well built trailers and I think they're better built "out of the box" than the Kaufman's. For example, both BT and PJ that I've seen come standard with round tube in between the stake pockets of the rub rails. To me, this is just a little thing that is going to help the trailer ultimately hold up better. That's not to say you can't order that from Kaufman, it may just be an upgrade where it appears to come standard on other brands.
A 10k trailer is definitely an upgrade, but I'd HIGHLY recommend just bumping up to a 14k simply based on how it sounds like that thing gets overloaded often (with drop down, spring assist ramps....FAWK slide-in ramps). Whatever you guys do, try to steer clear of 5-lug wheels...6 or 8-lug for sure.
Oh...and if for whatever reason baller budget comes into play. Diamond C ftw
@jeepinmatt will likely chime in before too long. I'd expect him to have some really good feedback / insight