A few manufacturers that I have seen and sat on in person that have great reputations for quality:
Taylor King
Wesley Hall
Hancock and Moore
Lee Industries
Baker
Lee is probably the most affordable of the the above. Crate and Barrel carries some of their offerings.
Others who also have great reputations, but I haven't sat on or seen in person:
Hickory Chair
EJ Victor
Hickory White
A quality sofa that will last will have an eight-way hand tied seat deck. The more minimalist models (eg: MCM) usually use sinuous springs since there isn't enough "bottom" to house the eight-way hand tied system. Sinuous isn't necessarily bad, but it's not apt to last generations like eight-way. But that may not be a consideration for you.
I really like well made furniture and have collected some discussions here on Houzz that you may find helpful. The best advice I can give is to take your time and do your research. Best wishes!
Furniture 101 Q7A
Great Sofa Manufacturers with Good Price Points
Middle to High End Upholstery
Q
ektorp sofa covers
Q