The winkl mattress was not for me but I want to give a positive review of the company. I found the mattress just not quite firm enough, as I like an extremely firm mattress.
The service from winkl was absolutely excellent. The terms and conditions were easy to understand, the mattress arrived quickly and the "return" process went so smoothly.
I definitely recommend trying the winkl, it is a nice mattress and probably comfortable for most people. I would have kept mine if I had room for a guest bed.