To help you get a handle on it all, we spoke to Amy Archer, a consumer behaviourist with Rowe Furniture who also spent 10 years as a furniture designer. She knows her stuff and she's prepared to share.
The inner truth
A lot of what separates the good from the best in a sofa is happening inside. It's the things you can't see that really affect how well your furniture takes a beating (jumping, bouncing, being moved around). The starting point here is the suspension system.
These systems are modelled after the ones found in car seats, and the Cadillac of sofa spring systems used to be the "eight-way," something Amy describes as "a slinky with attitude": eight metal coils attached to each other and then to the frame with two metal ties. "Everyone used to say, if you want a great couch, you need an eight-way suspension system," says Amy. Not anymore.
Some great sofas still use this system, but when Mercedes introduced an "S system" for their car seats, this model made its way to the furniture showroom as well. (Think S-shaped coils running through the inside of the sofa and attached to the frame.)
The latest incarnation comes courtesy of Ferrari, which introduced a webbing system in its seats. "Henridone and other high-end sofas come with this new system," says Amy. "It's like super memory elastic, and the great thing is it never hurts the cushions, because whatever the spring system is made of, it pushes against the cushions." Any of these systems will give you longevity and durability.