@douwe great that you bump in that quickly if we call you 
So beside the failure rates of the FP1(U) in general, I think it would be very interesting (and transparent) if you can break down the most often failure reasons (as I assume it will the USB port or the display…), and how you dealt with this (repaired the part, replaced the part, replaced the whole FP)…
Have nice evening at the Heldenmarkt@Berlin!
Cheers, Robert