There are other importers that have done quality work. Henry Bultmann springs to mind.
The correct way to look at this is:
Sunset/GGD etc. is simply the bestdollar for dollar in O Scale. I bring up Bultmann - his SP 4-10-2 was miles ahead of the Sunset version, but his price was triple!
I did Sunset reviews for 48/ft magazine in the 1990s and early 2000s, and got to see the Allegheny, Big Boy, NP 2-8-8-2, the various Hudsons, and that neat B&M Berkshire. All were simply as good as you could purchase for under four grand, and the ruggedness and maintainability put them way ahead of even the very high end imports.
I was only disappointed with the smaller SP steam - the Mikado, Deck, and 4-10-2 all came with straight boilers. But that's just me - most SP modelers are happy without the taper sections.
But again - best bang for the buck,by a mile! Go 2-rail if you have a choice.
Opinion.