I can’t give a long-time-experience account but compared to all my other hardware the switches and potis of the Octopus are excellent. Both are metal, the switches are tightly embedded in the surface but reacting very tight. So you can glide over them without "feeling insecure". The potis have a quite strong raster which is convient for counting steps and are rock solid.
I am no engineer but I feel very secure and comfortabel with the hardware (it feels much better than my nord modular G2)