Hi tescatlipoca,
The first place to start your mattress research is the mattress shopping tutorial here which has all the basic information, steps, and guidelines you will need to make the best possible choices … and know how and why to avoid the worst ones (including major brands such as Tempurpedic).
I don’t have a “top 5” list because each person can have very different criteria about what they are looking for and “brand shopping” is not an effective way to choose a mattress so my focus is on “how to choose” rather than “what to choose” so that you can identify your own “top 5” based on your own criteria and the parts of your personal value equation that are most important to you (see post #2 here).
The tutorial also includes a link to some of the better online memory foam manufacturers/retailers I’m aware of (in the optional online step) and many of these sell mattresses that use Tempurpedic mattresses as a reference point so that you can use your local testing on Tempurpedic mattresses as part of a more detailed conversation on the phone to help you choose which of their memory foam mattress would likely be the best choice for you.
If you let me know your city or zip code I’d also be happy to let you know of any of the better options or possibilities I’m aware of in your area.
Phoenix