I switched a few months ago and am pretty happy, once you find the right addons.

The reason I switched was some niggling privacy concerns and then discovering that google-chrome won't allow Ghostery to block doubleclick.

Firefox with:

  adblock-plus, 
  ghostery, 
  noscript, 
  requestpolicy, 
  refcontrol and 
  cookiemonster 

addresses all the privacy concerns. Then:

  add to searchbar,
  customizable shortcuts,
  duplicate in tab context menu,
  firegestures,
  open link in ..., and 
  sessionmanager 

give me pretty much the same UX as I had in google-chrome.