Fantastic post, Smrobs.
Beau goes fantastically in a bitless bridle, and when I do use a bit, he's in a french link contoured loose ring, or a mylar loose ring, and he rides like a dream.
I've never had to use anything harsher, although when I first got him they had a slow twist eggbutt snaffle on him. As soon as I could get to the tack store, he was put into a single link smooth full cheek and from there, we moved on to a rubber d-ring snaffle and then the loose ring, which is my all time favorite on him.
He does occasionally have issues with stopping/slowing down when he gets really excited, but that's when we go back to basics and work in an enclosed environment and do a little refresher course on his whoa. :)