I switched to Chrome the same day the beta was released mostly because of the speed. Nowadays I stay because I keep my passwords synced over my Google Account and I'm not sure if Firefox works with that.
Regarding speed: Firefox will soon switch to a new rendering engine, WebRender. It's at least as fast as Chrome's. Then Chrome's speed advantage should disappear.
Did that years ago when I switched back when Quantum came back; Firefox still has the good old venerable "import passwords from another browser" functionality. You just need to have your passwords sync'd to a local install of Chrome and Firefox can read them all and sync them with FF Sync (which does not force you to use Mozilla servers, btw; you may host your own server for max privacy).
It's not just their service. You can run self-hosted service for sync [0] and fully control it. From privacy point of view that's far more interesting than any other solutions I've seen.
I've been doing this for a while but the part I haven't managed to solve is that using your own sync server on Firefox for ios seems to require you to also run your own Firefox accounts server - which is much more painful to set up. Is there a similar easy guide for setting that up?
The way I have switched password managers is to run both for awhile. Overtime you move the ones you need. Eventually if you leave a couple behind you can always reset them in the new browser/manager. It's not as big of a pain as it looks going in.
Sure it does. I keep my passwords synchronized with a Firefox account through my Windows, Linux and Android devices. Works like a charm. I won't trust google to keep them.
That is the second most important thing why I'm using Firefox, I sync my passwords via my own instance of the sync server https://jeena.net/firefox-sync-15. I don't even trust Mozilla not to do something stupid with my passwords (by accident) and Firefox was always the only browser which allowed to use your own sync solution.