Great thread -- I had the pleasure/displeasure of learning how to drive/work last summer. (The guy who was "teaching" me, led to my leaving the job after a couple of days).
That being said, like anything else in this world, looks easy. Not quite so. I'll share some n00b thoughts on this.
Uses a crap load of hot and cold water - pain in the ass to fuel (some propane around these parts).
4 wheel drive has to be only used while on the ice, not anywhere else, so constantly, shifting back and forth. Took quite a while to get used to the accelerator feel. Steering and using the brush for the sides, was actually fairly quick to learn. Just a big machine with awful visibility which is why you see many people stand.
When you have ice buildup at the boards -- near the benches and corners, you need to cut the wash water while in those areas. Never truly got a feel for how much I was cutting, spinning that wheel, the only true indicator was sound and feel and ice ripping through the auger and into the tank. I suspect this comes with experience. I don't have experience.. LOL
And I MOST got yelled at for not running straight lines up and down the ice -- missing spots. Yeah -- that's how you learn.
And I was able to skate on the Isles' new ice last year, @UBS. Let me tell you-- after decades of skating on crap, if you ever have the chance to skate on NHL quality ice, please drop everything and do it. Was like glass.