Lee Industries perhaps.

Look for manufacturers that are made in the U.S.A. and offer a lifetime warranty on frame and suspension - that is usually a good clue it is made well. 8-way hand tied springs are the gold standard, and sofas that feature that usually have quality construction throughout the piece. Some manufacturers do good sinuous springs, but some do not, so it's a little more iffy. I'm partial to Lee Industries and The MT Company and also love Carolina Custom Leather for leather pieces. These are what I sell so am most familiar with them. A seat cushion with innersprings will hold up the best. Avoid down unless you are okay with flipping and fluffing daily.

Some other maufacturers that I've heard good things about are:

Hancock and Moore

Taylor King

Stanford

CR Laine (though I have read some reviews that their quality is suffering lately)

Thayer Coggin

Wesley Hall

You can find a local retailer on the retailer locator on the manufacturers websites.

Thank you both. I put another post on today with a photo of the type of sofa I'm looking for. I did some research on Lee Industries and it seems like there are a fair number of people who are upset with their quality.

Yes, I've read those threads and know that there have been some unfortunate instances (no furniture company has 100% satisfaction), but I've been selling Lee for years and have had 99% of my customers be very happy. I contintue to recommend them without hesitation. Just make sure you use a good retailer that can guide you with the correct fabric and cushions for your preferences and will take care of any issues if they arise. Any time there's been something wrong, Lee has worked hard to fix it.