So these thoughts are based on personal experience. I've had many examples from some of these companies.
WE/Sencut/Civivi, Kizer, and Bestech have been the best overall with the first two companies averaging better than the third.
Petrified Fish is great on the low end but tend to leave crisp edges on their scales. Lots of people in the community don't seem to care about that kind of thing so take that based on your own tastes. (I'm prone to sanding or filing scales in search of ergonomic improvement.) I'm not big on Chinese D2 but these guys seem to do one of the better budget heat treatments.
Ruike and Real Steel both seem to be made by Sanrenmu. Both of those brands tend to be okay. On folders, some people love them and they are notable for offering 14C28N at low prices. My experience with the folders has mostly been "okay". The best things I've seen from either brand have been fixed blades in either 14C28N or 9Cr18Mov*. Sanrenmu also makes a bunch of SAK-like multi-knives that are decent. They show up variously under these brand names and also as the Boker Tech Tools. As a manufacturer, Sanrenmu has made knives for lots of companies including Boker and Spyderco. Their named brand suffers from being made cheaply to sell at low prices, some mall-ninja designs, and a few knives that look suspiciously like Chris Reeve designs.
TwoSun is interesting but I have mixed feelings about them. On the one hand, their machining tends to be excellent. They also work with a bunch of different designers and offer some pretty interesting stuff. On the other hand, there has been some question on the quality of their heat treatments. They tend to go with overly thick blade stock. While some people see detent ramps as a premium feature, they often interrupt my usual closing method for flippers. Also, their entry into this price category is based on their atypical distribution in the US where lots of stuff goes through an authorized dealer on an auction site. They have a new budget brand called SixLeaf but the one example I tried had an issue. (They put an aggressive texture on the blade that the detent ball had to skip over. This had an unfortunate effect on the action.)
Harnds doesn't release a lot of new models but they continue to offer a few standouts in the "under $50" category. The Talisman remains my favorite.
Trivisa is a new manufacturer who seems to be decent but I only have one of their knives. I'm curious to see where they go.
CH CH Knives is interesting in that they often make knives for other companies and don't have much in the way of direct distribution over here. They were notable for being the only trustworthy knives distributed by Eafengrow but more on that in a minute. My main issues with CH have been inconsistent quality control, knives leaving the factory with strong-smelling oil, and regular use of permanent thread-locker.
Eafengrow Avoid like the plague. They are a rebranding distributor and infamous for stamping whatever steel they think will sell on pieces of 8Cr13 or 5Cr15.
Artisan/CJRB Too many lemons. Yeah, I'm just one guy but one guy should get like five lemons from one company.
QSP Also too many lemons... maybe six?
* Note that 9Cr18Mov in the Civivi and Sencut knives gets an exceptional heat treatment and will perform better than if you get that steel from any other manufacturer listed here. It's otherwise a decent budget steel and generally still a big step up from the best 8Cr13Mov. It's just much better in knives from the WE brands (including the stuff they make for Ferrum Forge).
