I’ve been using it for about the same amount of time. I’ve added a few add-ons, and have used it continuously. No problems. I can’t say FR is much (if any) faster, but Firefox does seem to boot faster. I haven’t had to reboot my PC during this time, so I can’t say a fresh Firefox boot will be any faster.
I think it’s definitely faster and improved. I go to a lot of different websites and load other things into memory so there’s was a lot of opening and closing of websites and other applications before it locked up.