As someone who made the switch a month ago, here's the problems I've felt - but they are not major I warn you. I still use it.

1. Firefox's private window still runs your plugins - its not a sandbox clean browser 2. You still have to restart if you installed a plugin (ugh! its 2015) 3. You can search from the address bar, prepend a "?". i.e "?google.com" will search with keyword "google.com".

Otherthan this it was a joy to use firefox - works faster than my "chromium" build on osx yosamite.