Was absolutely wonderful when I first bought it. Turned it as per instructions every week for the first month, then monthly after that.
I only weigh 11st, sleep alone and no "action" in this bed, so it's not been abused in any way.
Started getting neck pain and realised it was caused because the mattress has gone very soft, sagging in the middle where my body is.  Where my head is it is still firm so that's why it's putting strain on my neck.  It's only 3 monnths old (my last spring mattress lasted 15 years!).
Hugely disappointed. I'm now sleeping in my spare room on a sofa bed while I wait for another mattress to be delivered from another company.