As far as I am aware, all, if not most of the planes have had the FlareAssist installed. I have gotten great feedback from the pilots that have used them.
As for my wing man and myself, we love it so far. We fought a fire near Bethel, AK a few days ago. We did about 36 scoops in roughly 2 hours. We were scooping in a river so glassy was not a problem, but as the dusk continued, we were scooping into the sun, which can greatly affect depth perception, and the flare assist was great in helping not waste waterway behind us.