I worked on E series and the older Mac's for over 20 years, and like any HMI and operators with hands like sledge hammers, pens & knives to use as a stylus etc. there were failures but to be honest seemed to be more robust than the AB Panelviews (plastic that dropped apart) and Omron etc. In the early days you could buy the keyboard as a stick on (on keyboard versions) and these were quite cheap, however, for some reason the keyboard then turned into a complete front so a little bit more expensive. I have not done many GOT's so it's early days yet, one other thing I found was dull screens was often down to the reflective foil on the back of the strip tube peeling it was like a type of self adhesive foil that peeled back this was easy to rectify. In my last position we had over 70 E HMI's, 20 or so AB, A few Siemens and a few Omron, the E series were far more reliable overall. In fact I replaced most of the AB ones for E series this cut our repair costs by over half , although this could have been down to age in some cases.