Depends on the model. I'm trying to find a used Eames Aluminum group chair for a reasonable price, but people just want too much for a 20 year old chair. That said, they are some of the greatest chairs ever made.
The Aerons are a ripoff and, IMO a total departure from other Miller designs. I really dislike them on the basis of design and I think they just plain look tacky.
There are a dozen or so other designs I'd love to have in my home, other than office chairs that I would gladly pay the premium for, could I afford them.