We have a Tempurpedic and absoulutely LOVE it!!!! Wish I could tell you what model but I really don't know. We have had ours for approximately 3 years and I sleep so much better than I ever did on springs...and, no more hip pain for me in the mornings!!
Some things to keep in mind about Tempurpedic:
The foam is temperature sensitive. The mattress will be firmer in colder temperatures and cushier in warmer temps. I acutally prefer mine in the summer, my dh prefers the firmness in the winter (we keep our house pretty cool). ALSO, very important, you cannot use any heating elements with it such as an electric blanket or heating pads.
With Tempurpedic there is no need to flip the mattress, which is very nice.
The Tempurpedic is not bouncy...the pros of that, less movement when your partner moves around to change position. The cons...less bounce for "extra-curricular" activities, if you catch my drift.
I believe the Tempurpedic comes with a guarantee where you can return it after a certain number of days or a month or something if you don't like it.
Don't spend extra on tempurpedic pillows unles you try them first. While I LOVE the mattress, I cannot sleep with the pillows.
The tempurpedic is pricey, but considering how much of your life is spent sleeping and how many health issues can be caused or precipitated by poor sleep, it seemed for us an investment in our health. BUT, we also had a memory foam mattress topper for several years so we knew we were probably going to like it...that might be a good place to start.
Good luck with your decision.