I love my IKEA Hesstun. 2 separate sets of coils (I prefer springs to memory foam), a comparable design from the major brands was about twice the price. IKEA offers a transparent profile view (i.e. the inside of the mattress) for every mattress they sell, and you can lie on every one for hours without a single salesperson bothering you. 365-day exchange policy, longer than any of the stores I visited was offering (IKEA allows exchanges, but not refunds on mattresses). People knock IKEA but I do not believe my mattress is inferior in build quality to an assembly-line mattress from Sealy, Simmons, etc.

I know my mattress has low ratings online -- this is meaningless, all the review sites are just commissioned salespeople for the online brands (Casper, Purple, etc), so of course those sites discourage you from buying from IKEA.