Compare the "Literature summary of biomechanical simulations for wear" table at:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4705139/
I'm concerned about the PCU aging and plastic deterioration. But when you compare the (apparent) debris generated alone from the ProDisc vs the ESP... And all that metal and plastic that would be thrown out from the ProDisc comparatively...
To be fair there are pros and cons to all of the discs out there. I think the risk vs reward of the ESP is the best. How many completely independent super-respected doctors still use the ProDisc...
Desai, Clavel, Berg, others in Germany, Switzerland... Using the ESP.
And unless we're running, few of us are putting 300lb of pressure on the disc. I know some people go back to weight lifting, etc... I'm going hopefully enjoy my discomfort-free life, improved ROM, etc... And not press my luck.
Good luck - please post an update when you feel up to it in the coming days...