I originally bought mattress in 2006 and it started to sag shortly after and kingsdown replaced it in 2011 with a far inferior mattress than what I had. My wife and I could not sleep on it , it was like a concrete block.
I immediately called customer support and complained and they said to me " too bad that is your problem and we can do what we want". I fought with them for a month trying to get and equal mattress to what I originally had and they said no too bad. I spent an additional $1000.00 to get one of there best mattresses and let me tell you what a piece of crap this thing is.
Customer support did nothing. I wanted to file a formal complaint with the BBB but I let my wife talk me out of it. This I regret.

I purchased a Kingston "SLEEP TO LIVE; CHAIRMAN", ROYAL AND NAVY FIRMNESS, which is a very new model as of the end of 2010, we read mostly bad reviews, but all of those reviews were of the previous models before Kingsdon did some major revamping. Creating new mattresses. I am writing this review almost a year later because I feel guilty for complaining about our mattress in some review when we first slept on it, it hurt our backs. But after a month of getting used to it, my wife and I absolutely love it! It is by far the best mattress we have ever slept on. Feels like something you would feel in a Four Seasons Hotel Presidential Suite. We love that we each were able to choose our own firmness sides. My only issue is we are about to move back to Ohio from Las Vegas and this is not only the most comfortable (after the initial few weeks of our bodies becoming used to what a high quality mattress feels like) but this is also the most heavy mattress I've ever felt. What a pain in the ass to find a fitted sheet too! 20"+ deep! But absolutely no regrets, a great investment, expensive, but worth it. We recommend trying it at the store. We bought ours at MATRESS Firm, who by the way have good prices but always will try and up sell you. Tell them to leave you alone while you find a few mattress you like, then they can talk to you. Also this mattress brand does a body test to tell you what firmness will be good for you. We didn't use it, we went with what we liked laying on in the store. I knew I like soft for my painful wide shoulders and my wife likes firm for her lower back. Have them deliver it for free! Heavy! Also invest in the memory foam pillows, wow! But I think we could gotten them cheaper elsewhere, maybe, mine was $200 and my wifes, the smaller one was $150. But worth it. We were sleeping on an air mattress for 7 months before I bought us this, and a beat up sunken spring mattress before that, we paid $200 for from Mexicans in Vegas. Whoops, get what you pay for. So check out SLEEP TO LIVE , CHAIRMAN. It's about one year old now. Don't worry about a newer version, this one is perfect, you don't feel anything in between the two different firmness sections of the bed, I remember reading that in reviews, that must be with the older versions. What makes our mattress very good is not only the memory foam, but the LATEX. Haha. Seriously. That's what's in it. Good luck. We spent few grand.

this bed has caused me so much back pain. It sags so much within a week and I constantly am feeling the bed pull me towards my husband while I'm sleeping as it starts tilting at an angle due to his higher weight. do not get scammed by sleepys. beware