Hi,
Sorry I don't have any experience with the x-stop. This is the surgery that my surgeon wants me to have and I also have been trying to get information.
I have stenosis and was told that this surgery is less invasive than a fusion, less healing time, less painful, and that within a year would know if it helped.
I wish you luck with your decision, I know how hard it is. Hopefully someone whose had this will respond.
Take care