Oh... and I have a king-size SpringAir with a foam wrap around the outer sides. Love it, love it, love it. I can't tell you what model it is... except it's one level down from the individually wrapped coils, which seemed pointless.
I can second the whole SpringAir matress. We love ours!
All stores model names are different by chain, even though the mattress may be made identically. We got the Queen-size "Brasswood" model from US-Matress.com. They have a demonstration showroom up in Plymouth 453-1300. We paid ~$2,100 for the whole shebang with tax. No flip, no rotate..
Scratch that.. It is a Sealy SpringFree.. No springs..