Hi needanewmattress,
That’s something that I can’t answer because I don’t know the raw material or component costs for either one and of course I don’t have access to all the business information that would affect how any specific business prices their mattresses but post #14 here has more information about many of the variables that can be involved in the pricing of a mattress. Flexus is also a factory direct manufacturer and Berkeley Ergonomics is a wholesale manufacturer that sells their mattresses primarily through retail stores.
That would depend on how you define “superior” and on which of the pros and cons of each type of innersprings are most important to you and on which mattress that uses each of them is a better match for you “as a whole” in terms of PPP. There is more about the different types of innersprings in this article and in post #10 here.
Phoenix