Hi Pattycake,
Thanks for taking the time to share your comments and experiences … I appreciate it.
Unfortunately your experience is far too common with the major brands (such as Sealy/Stearns & Foster, Simmons, and Serta) because they all 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 which is why I would generally suggest avoiding all of them completely (and the major retailers that focus on them) 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).
You certainly made a better quality/value choice this time and it’s good to see that you came to realize that there are still many manufacturers in the country that make two sided mattresses.
Congratulations on your new mattress 
Phoenix