I have used mine as my main pad since they arrived at the works. The case is still in v.good condition and the foam is as good as new. I think they are excellent and will happily get another one when mine eventually dies but that doesnt look to be any time soon. They are good as a single pad and mega as the top pad in a pile. I will be hulking mine around hen cloud on sunday if you care to fall onto one, or you can rent one from the works, i think.
Quite expensive but i would price my knees at more than a few hundred notes.