I am 5'6 and 150 lbs my husband is 5'11 and 250 and we both are sore every day we sleep on this mattress.
The store did not offer every configuration and I was left to choose between soft med firm and med med firm ( all Dunlop) so the problem is that lying on the med does not immediately feel uncomfortable. It feels pleasantly supportive. Spend a night on it and it is a whole different ball game. Makes it impossible to trial in a show room. The other problem is the are taking their time shipping us replacement layers. I doubt that exchanging one layer will help all that much.
This was an expensive mistake.
Not recommended unless you live in the city these beds are made in and can try every configuration.

I can't say enough about the wonderful customer service from FloBeds! Five months ago I ordered a latex mattress from FloBeds in California to be delivered to Atlanta. It arrived in a little over a week. It took a few weeks for me to figure out the best fit, but the company was exemplary in responding to my requests for exchanges and refunds, when I wanted to try a different firmness and later return a foundation when I decided to keep my low profile box springs. No questions asked. There was always a prompt response to my concerns, and I am now sleeping soundly. I sleep deeper on the latex mattress as there are no "pressure points" with latex. I discovered I needed the V-zone because I am a side sleeper. Whereas a medium firmness supported my back, it was too firm for my shoulders, so I have a soft section under my shoulder. I highly recommend you order the V zone if you sleep on your side. Latex is supportive in a way memory foam is not. It only gives so much, unlike memory foam, which seems to just sink and makes it harder to get out of bed. It takes some time to get accustomed to the different feel of a latex mattress, but I am sleeping more soundly, not waking several times in the night. The FloBeds system of layering different levels of softness means that you can customize the two sides of a king bed to different firmness levels. This was important for me since my husband is about 100 pounds heavier. With latex, your weight determines what firmness you need for support. I am 5'8" at 145 lbs and am comfortable with XF on the base, Firm in the middle core with a Medium V-zone on top. My husband usually likes a softer feel to his mattress, but he ended up with SuperFirm as a base, XF in the middle with a Medium on top without the V-zone. Latex does NOT sleep hot like memory foam, which was a big concern for me. The cores are perforated with pencil size holes which allow it to "breathe". I have adjusted the firmness level several times by myself as the cores are not too heavy to handle one at a time. Flobeds only charges for shipping if you request a different firmness level core if your first preference does not feel right. It took me a couple of months to get accustomed to the "no pressure point" feel of latex. At first, it worried me that I didn't *feel* the support, but I was not having back pain that a soft mattress usually gives me. Plus, I was dreaming a lot more (more REM sleep), so I stuck with it. No complaints about the company. Highly recommend. Even after the 100 day window had just passed, they gave me a full refund for the foundation I bought from them when I decided to reuse my old box springs.

This mattress has helped so much with the pain I would get in my hip and back from sleeping on my innerspring mattress with a memory foam topper. Unlike the memory foam, latex does not sleep hot. I really don't remember if the latex mattress I bought is considered Serenity or Tranquility. I was fortunate to have a Savvy Rest store nearby so I could try out both the Talalay and Dunlop layers in different degrees of firmness. It is great that you have up to 90 days to exchange layers, as you really can't tell in the store how soft or firm the mattress feels until you sleep on it for several nights. I switched layers two times (easier to do if you buy a split layer rather than a solid piece). Also bought the adjustable bed. I can't wait to go to bed at night, and it's hard to get out of bed in the morning, as it's just so comfortable.