I’m not really sure what the fuss is about. I couldn’t even see a difference, updated and came back the same ol Firefox. People whine too much.
The only thing I find extremely irritating is that FWD/BACK and REFRESH are tied into the address bar - I prefer Home, Back/fwd. and Refresh to be in the far left of the bar, as they are what I use primarily, and need to be in that premium real estate. I can still get an approximation by moving buttons, but refresh is tied hard to the right side of the address bar.
I know... F5... or RClick/Refresh... But it bugs me.