If it had to do with the electromechanical hydraulic valves, it failed, switches, circuitry and the valves themselves. These were on Yale electric fork trucks that were rebadged with the Hyster name. The valves are crap, the switches are crap, the controller modules are crap and the connectors are crap. What made it worse was that these electro valves were buried in a position in the truck that made them all but totally impossible to change.
This system has been on these trucks for three years that I know of and they have made no progress in improving it.
Maybe these were the only electro hydraulic valves and systems that ever gave trouble in the entire history of such technology, but it's enough to make me stay away, FAR away from any equipment utilizing hand operated, electro hydraulic valves.
If there were something to be gained by using them, then I could be patient and await their perfection. From where I sit, however, I see absolutely no advantage in them as they are currently used. You have a control of some sort that actuates the valve. What is gained? A handle can RELIABLY actuate a hydraulic valve.
NOW, that said, if there were some computer control of electronic valves that allowed for some complex, intelligent actuation of these valves, THEN there would be a reason for using them, so that the computer or other complex controller could actuate them. For hand operation of a valve, however, stick with the good ol' reliable, lever actuated valve and save yourself, money and headaches.
My $0.02,