Hi gm968,
There is more in post #9 here about “matching” one mattress to another but unless a mattress is specifically listed or described as “approximating” one of the Tempurpedic mattresses you would either need to test them in person to see how they compared in terms of PPP or if you are dealing with an online retailer or manufacturer that is familiar with the Tempurpedic lineup then you could talk with them and ask which of their mattresses would be “somewhat comparable” to the Tempurpedic mattresses you are considering.
I would generally suggest comparing all the mattresses you are considering against a common set of criteria rather than trying to “match” the other mattresses you try against any specific mattress which may not necessarily be the best “match” for you.
These types of comparisons can also be very subjective and different people can have very different ideas of how closely comparable two mattresses are in terms of PPP.
Nobody else can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved for someone else to make these types of suggestions based on a formula or “theory at a distance” for someone else and what is the “best value” for one person can be very different for the next. I’m happy to help with “how” to choose but the specifics of “what” mattress to choose in terms of PPP or “value” is too individual to make specific suggestions (see mattress firmness/comfort levels in post #2 here). There is more in the tutorial post about “how” to find the best value for you (regardless of whether it would be the best value for someone else) but in general terms the “best value” would be the mattress that was best for you in terms of PPP and all the other parts of your personal value equation that are most important to you once you have narrowed your options down to final choices that are between “good and good” (step 5 of the tutorial).
Phoenix