Honda and Yamaha have traditionally been the cream of the crop.
HOWEVER
In recent years, the off-brands are really coming into their own. I've had a Champion 3200 for about 6 years, absolutely no issues. And believe it or not, the Harbor Freight 3500 I bought last-minute two years ago (because I forgot that I'd loaned out my Champion), has been great. It successfully runs all the 30A requirements on my RV, and during Icepocalypse 2023, my SIL lost power for almost a week, and it ran pretty much non-stop that entire time, with no issues at all.
Anyway, I wouldn't shy away from the Champion or some of the other off-brands, just because they're not Hondas and Yamahas. Ten years ago I wouldn't have said that, but I've had really good experiences with the Champion and the Predator (Harbor Freight).
Just one thing to note-- to hit that <$500 price point on a Champion 4000W dual fuel, you're looking at what they're calling an "inverter open frame." I don't have any experience with that. The standard open frame ones, are incredibly loud and will make you hate your life. Standard inverter ones, are all closed-in and don't have that open frame, and they're much quieter. But an "inverter open frame" is something I've never used and don't know anything about. Definitely worth checking its specs and if possible listening to one in real time.
Good luck!