I'm down with some fates. Been enjoying the hell out of it, the only thing that irks me is the idea of playing casual mode. I couldn't imagine enjoying my game if I wasn't risking my beautiful units. Birthright is too easy, doesn't feel like a classic game with limited EXP. If Birthright was the only path, I would be as interested in Fates as I am SS which isn't much at all. (Haven't played Rev)
But I have only been an on and off player: played Binding Blade, fe7, SS, PoR, and Fates. The best thing about fates for me is having 3 routes and playing styles (feels like 3 games in one) , and having that time in the castle to explore, prepare, and learn about your units and supports.
My preference goes 7, BB, Fates, PoR, SS