I sent this question to Hawaii_Jake, who used to sell mattresses. He is our resident expert.
As someone who worked in the hotel business for 30 years, I can tell you this: Mattresses fall into what I call “The Goldilocks Syndrome”. Some are too hard, some are too soft, and some are just right. It all depends upon the perspective of the individual.
My advice is to try both the Tempur-Pedic and Serta. I’ve only slept on the former once (for a week’s stay) and it wasn’t to my liking, but many people swear by them. The hotel chain I worked for did an extensive study on mattresses and found that the majority of their customers loved the Serta mattress the company chose. It was quite shocking how many of our customers complained about how comfortable the mattress was…they didn’t want to get out of bed. Here is a link to the mattress information.