I've been using this for a couple months after using McFly in zsh for over a year. I think I can say that I like it better, but the only thing I sometimes don't like is how it completely takes over your screen when you press the up arrow. I usually just want to get the previous command I entered instead of the whole searchable history (which I use Control-R to bring up), and it's really jarring to have the entire screen change. Aside from that, it's really awesome to have everything synced across a bunch of machines.
Same here, but you can disable that behaviour, and then it’s nicer [0].
I also find that I prefer the default Ctrl-R to start with history from the current directory instead of the global history, but that is also changeable. So I’m pretty happy.