There is a 4th option as well that you can get info on if you call and talk to them. It is one made for OEM installations, and is considerably less expensive than the others shown on the website. It comes with 9 springs connected together in a square mat which is trim-able to the size required, and there are 2 different firmness levels. We have had it for the past two years, and have been happy with it, but as far as I know we are the only ones in this group using it, so not a lot of comparisons to go by, but wanted to let you know there is another option to consider. If you look in about the middle of this forum page
Memory Foam Or Some Other Type Of Mattress Topper? Need Advice! you'll see some pics I posted along with a brochure pdf from Froli on this option.
Hope that gives one more option to consider.
D & K