It's a real challenge to say one is better then the other. Generally speaking higher quality comes with a higher price line, but without spending some time getting to know it's hard to tell which just put a bunch of shiny objects and which are dedicated to bottom line quality. For the most part the the average mass built RVs are pretty similar. If you get a Friday afternoon edition you might have problems, but the ones that came out on Tuesday might be better.
I think the Desert Fox line are very well made, but they don't have a lot of models and no FW units any longer. I'm hearing and reading a lot of very good things about the Grand Design and EverGreen line ups, but they are still fairly young, hopefully quality stays up as their popularity rises.