What a joke this is.
I don't care what they call Firefox starting with version 57, I'm still not interested in the least bit. I'm on the ESR channel now with version 52.3.0 and that's where I'm staying for as long as I possibly can. Here's why: https://github.com/Aris-t2/ClassicThemeRestorer/issues/299 I also set Firefox to never check for updates. I want to have complete freedom to choose when I install the next ESR version.
I have nearly 30 legacy extensions that I absolutely refuse to live without. CTR is just one of them.
I recently spent about 2 weeks with the normal version of Firefox 55.0.3, but I kept having minor problems that ended up being a daily frustration. I was tired of living with it and tired of trying to fix it and I could tell it was due to a couple of my legacy extensions, so I said "screw it!" and went back to 52.3.0 ESR and now I no longer have any problems whatsoever. Sure, 55.0.3 is noticeably a bit faster, but I don't care. I wouldn't care even if it were 100x faster. I care far more about having complete customizability and the best functionality that I can possibly get. If I cared more about speed, then I would've switched to Google Chrome a long time ago.