Years ago, I had an early version of Flow bindings and they were rubbish - constant fiddling with the tightness and the hiback closing system always felt loose and sketchy. So I was a little bit sceptical about going back to a step in binding, but had seen so much hype about the Supermatics that I felt I had to give them a go.
The conclusion is that they are totally worth the premium price. Even just on time saved alone - no more sitting down at the top of the lift, fiddling with ratchets, winding up any mates on skis etc...
They do take a little bit of getting used to. The initial set up is pretty easy and you can make small adjustments to the ratchets for comfort as you get the right balance of comfort and tightness right - once you've got them all locked in as you like, I found they stayed exactly where they were for the rest of the trip.
There is a knack to stepping the back foot in as you have to remember to push back on your heel to lock the heel plate/hiback, but you quickly get used to it. Similarly, stepping back out requires putting your weight on your toes - the lever releases the heel plate and if your weight is on your heel, you just end up locking it straight back again. Again, once you get used to it, after a few goes, its super easy.
I reckon I must have saved at least 2 hours over a 4 day trip, by not having to fiddle around with straps anymore and by the end had got to the point where I could kick my back foot in whilst moving after getting off the lift.