Hi prairiesun,
Welcome to the Mattress Forum! 
While I appreciate your opinion about these mattresses, it is a perfect example of why I advise people to not use someone else’s opinion, either pro or con, to pick out a mattress or as a reliable source of objective information.
As I mentioned either in this thread, Mattress 1st is a Serta house brand carried by a group of independent retailers who are part of a purchasing group (furniture1st ). The value of any particular model such as the Royalville plush would depend on knowing the specifics of the layering (which being made by Serta is not likely to include the density of any polyfoam in the mattress which means a blind purchase with no way to know the durability of what you are buying). I would put them in the same group of “major brands” that I would tend to avoid because of the likelihood of lower density foams and lack of transparency of the ingredients in them.
Unfortunately, all the major brands (such as Sealy/Stearns & Foster, Simmons, and Serta) tend to use lower quality materials in their mattresses than most of their smaller competitors that will tend to soften or break down prematurely relative to the price you pay and I would generally suggest avoiding all of them completely along with any mattress where you aren’t able to find out the type and quality/durability of the materials inside it (see the guidelines here along with post #3 here and post #12 here and post #404 here ).
It’s unfortunate that Mattress 1st chose not to include any meaningful details about their products in their new web site, even though back in 2012 they said they would review with management these posts and requests for actual data about their componentry when launching that new web site.
There is certainly nothing about Mattress 1st that would give me a reason to consider them, especially when compared to many other choices that use higher quality materials that don’t have any “weak links” in the mattress and are more transparent, and would be a much less risky purchase, IMHO.
Phoenix