The most frustrating aspect of dealing with this company was their return policy. Be advised that should you have ANY issues, they require you to send the entire chair back to them for service. To be fair, they will cover any problems with the chair, but you will be covering the shipping (as stated in their warranty), which, for a chair, was around $50 each way for me. So a $600 used chair could end up costing you $700-$800 or more over the life of the warranty.
One of the problems that I had concerned one of the chair arms breaking 7 months after purchase. Initially, the company insisted I spend $100 on shipping the entire chair rather than allowing me to send only the broken arm. After I refused, they told me the other option was to sell me the replacement part (they valued the part, a bolt, at $39.99. I bought one at the local hardware store for $0.58)
After much back and forth, the company, to their credit, did offer to send the part I needed as a one time courtesy, after which, should anything go wrong, even another bolt breaking, I would have to strictly adhere to the warranty as stated (i.e. $100 shipping). In the end we were able to resolve the issue. I purchased a part locally and repaired the chair on my own.
EDIT: Annie, the supervisor has informed me that despite the original email they sent me, the company does work with customers to provide courtesies like additional parts where necessary)
tldr - The prices on the chairs are great and the company WILL honor their warranty as written, but for even small issues expect to pay full shipping each way, which can be expensive.
FINAL NOTE: The customer service was initially unpleasant to deal with and very curt, but the managing supervisor, Annie, was incredibly nice and did a great job explaining things to me in a pleasant manner, once it escalated to her.