As has been mentioned most will recommend their particular brand as the "best". In my case, I found a floor plan I liked, with lots of room, from a builder I believe has a good reputation, bought it and haven't looked back (other than wondering if I went with too long a vehicle :B). There are things I wish were different on what I bought, but I was willing to give those up because of (again to me) the reputation of the manufacturer.
I see others have mentioned Born Free and Lazy Daze as being among the best. I was in one Born Free probably 20 years ago at an RV show (it was very nice) and have never been in a Lazy Daze and I'm sure it's equally nice. You should however ask yourself how much do you want to spend for the "difference in quality" real or imagined.
In my case I bought a 32 1/2' motor home with one very large slide out for $60,000. I just checked the Lazy Daze web site and their 31' long model with no slide goes for $97,500. I'm sorry but to me that's way too much a difference. Others obviously don't care about the difference.
Best of luck in whatever you decide to go with.
2014 Itasca Spirit 31K Class C
2016 Mazda CX5 on Acme tow dolly- 4 trips ~ 5,800 mi
Now 2017 RWD F150 with a drive shaft disconnect