My wife and I bought a Tuft and Needle king size mattress after reading jlcollinsnh's article.
http://jlcollinsnh.com/2014/10/26/tuff-needle-a-better-path-to-sleep/It retails for $750 and we used a special offer through AMEX and got a $100 dollar statement credit 3 days after we bought the mattress.
After sleeping on the mattress for 10 days, my wife finds it a little too firm but I find it just right. I emailed T&N and within 10 minutes, they responded and gave us a $70 credit to buy a recommended mattress topper for my wife's side, no questions asked. I realize it is in their interest to avoid a refund request but I still think it is awesome for them to offer money without prompting.
They also have a 100 night trial period and if you decide to return the mattress they will give you a free refund and have the mattress donated to charity.
Outstanding customer service and I highly recommend their product if you are in the market for a good bed at a good price. Also, look for the special offer if you have an AMEX at the bottom of the AMEX account website.