Editorially, it has a bias yes. But it’s non political pieces are decent. Plus the Games section isn’t too shabby.

I could be wrong, but Washington Post I once tried and I found it even worse. Guardian is slightly better.

Yes, I have been using for some time. Works like a charm on the supported websites. Can even be installed on mobile Firefox if extension sideloading is supported. (Dunno if official Firefox supports it now but the forks Iceraven and Smart Cookie Web Preview do).