The problem with the Shockpad seems to have been resolved at the Terra Fi 4. There now seems to be incorporated into the brine. I think at the Terra Fi (first model), it was that way. The problem with the 4 but the greatly raised Sole edge. This causes at least for me with runs very quickly bruises on Fußsolenrand. Very uncomfortable. I have the sandal still twice as attracted and then they are no longer used. I feel worn as not comfortable. It may of course be an incompatibility with my foot.
As a very good and even cheaper alternative I can Teva Terra Fi Lite M recommend. I have now been in the Lite behind me and no problems many runs. The Teva Terra Fi Lite M is not only much cheaper but also much lighter than the Teva Terra Fi 4 M.