I think there is a huge difference between early ECLE editions and the ones they are cranking out now. I'm not an operator, but I did take mine (Ruby Red, build date september 2015) to MAGFest where it got over 900 plays in 4 days, and it held up fine.

Like I said, if you get a new one now, it will be reliable. It's been in production for several years at this point and they've got the kinks worked out. (That said, NO pin is perfect, and most NiB pins, regardless of manufacturer, require some adjustment after unboxing).

As far as code goes, it's got some of the deepest and best code of any pin there is, and the recent updates are great. I'm not sure the code affects overall reliability much, though.

to be fair, if you get two Sterns, that's twice the maintenance of one Stern. I doubt WOZ is more than twice the maintenance of a Stern. (although there are probably those who would argue that point )

there are a ton of features, but i don't think any particular feature is overly complicated. starting multiball (Rescue or Emerald City) is pretty straightforward --

EC Multiball: light each lock by spelling "scarecrow", "tin man", and "lion". lock each ball by hitting the ramp. lock 3 balls for multiball. couldn't be simpler.

Rescue Multiball: hit the two monkey targets to light the winged monkey. send the ball to the winged monkey, who locks the ball in the castle (thus capturing Dorothy). go to the castle, spell rescue, bash the door down, and enter the castle. viola. Rescue Multiball.

to be sure, if you are trying to win a tournament, there are all kinds of nuances in terms of stacking modes and stuff if you really want to get super huge scores, but anyone can walk up and pretty much figure out those 2 multiball modes.