I don't own Prodigy, but had Revolution for 4 weeks. One suggestion would be to keep an eye on those box springs. You'll need to get down and hands and knees with flashlight to see how much flex there is in the center slat down the middle / bottom of each box spring. However much flex there is, is how much the mattress is automatically going to sag, usually in the middle.
Personally, I'd feel better about having the mattress on a solid top foundation (i.e. Tempurpedic or the icomfort adjustable base). I saw what happened with the iComfort box spring that came with my Revolution. I'll tell you if you want to know.
I do know the Prodigy is built up like this - 6" core foam, 2.75" gel memory foam, 1" latex and 3" Koolcomfort memory foam. Oh, the ad board will say 2" Koolcomfort, but a simple tape measure test will easily show there is 6.75" of memory + latex foam above the core. Can feel the core seam easily at side of mattress. Even easier if you unzip the cover a little at bottom and feel up in there.
Reason I mention this is 5.75" of memory foam is a lot. It's a very plush mattress, but if you and your back like it, that's all that matters.