Hi Mattt,
Post #1 here is the best place to start with any mattress research and has the information, steps, and guidelines that can help you make the best possible choices … and perhaps more importantly avoid the worst ones (which would include all the mattresses you have mentioned from Sealy, Serta, Tempurpedic, and Ashley)
Sealy doesn’t provide information about the quality of the material in their mattresses which is one of several reasons I would suggest avoiding them and the other major brands which also don’t disclose any meaningful information about their mattresses and in most cases also don’t have good value compared to many other choices that are available to you.
Sometimes some “alternative” sources can provide some information about these mattresses and in the case of the Optimum lineup you can find some information about the materials inside them in post #48 here.
To the best of my knowledge … the Elation has 2" of the 3.7 lb gel memory foam and 5" of the Optisense 4 lb memory foam under this and they use the higher quality Opticore Plus base layer.
This would be a soft mattress and with 7" of medium density memory foam would also be fairly risky in terms of alignment and durability.
Since a mattress is only as good as the quality of the materials inside it… I would focus my attention on manufacturers that are completely transparent where you don’t have to guess at the quality or value of the mattress you are buying and can make more informed decisions and meaningful quality and value comparisons.
As you discovered these are not “unsold” mattresses (there would be no reason at all for a big box store to sell them to another retailer if they were new) but various types of used mattresses that are probably either warranty or comfort returns that were previously purchased by someone else and then returned or exchanged for another mattress. If they were new then they would have a factory warranty and would not be sold “as is”. These types of retailers are very much “buyer beware”.
As you can see in mattress firmness/comfort levels in post #2 here … I don’t recommend specific mattresses because there are too many variables and unknowns for anyone else to know which mattress design would be more suitable for you but the original “read first” post includes a link to some of the better online memory foam mattress retailers or manufacturers I’m aware of and one of these (Dreamfoam/Brooklyn Bedding) is a member here which sells a line of mattresses on Amazon that includes some memory foam models. Again though … the transparency of the manufacturer and their knowledge and experience along with their ability to help you make good choices in terms of which of which mattresses they sell may be most suitable for you is a key part of a successful purchase. I would tend to avoid retailers (either online or local) who are more interested in selling you whatever they can instead of helping to educate and inform you about their mattresses and the quality of the materials they use.
You can read my thoughts about mattress reviews in post #13 here and as you can see they will tell you very little about the quality, value, or the suitability of a mattress.
Once you get to step 3 in the guidelines that I linked … then the better options and possibilities I’m aware of in the Orlando area are listed in post #2 here.
Phoenix