Hi at rerst,
They have an ongoing sale which changes in its details.
I’m happy to speak to the quality of the materials in a mattress but as you can see in mattress firmness/comfort levels in post #2 here … the best source of information about the comfort and/or support of a mattress is either your own personal testing on a specific mattress or a close equivalent or a more detailed conversation with the online retailer or manufacturer that sells it. They know more about their mattresses than anyone else. In the case of the Grandis you could test the Tempurpedic Grand Bed for PPP (Posture and alignment, Pressure relief, and Personal preferences) which is a close equivalent to the Grandis.to get a sense of how it feels and performs.
I’m not sure of which Flobeds mattress you are looking at but they are also one of the members here which means that in terms of quality, value, and service they both compete well with the best in the country.
The first step is to narrow your choices down to one at each retailer or manufacturer based on more detailed conversations with each of them (step 4 in the basic guidelines here) and once you have eliminated all the “worst” choices and are down to “good vs good” choices then to make your final choice based on all the objective, subjective, and intangible factors that are most important to you.
Phoenix