Monica

There are bubbles.

I know this, because I've been angry at Mozilla about this for nearly a year now.

On the other hand:

57 is much, much faster and much, much less RAM-hogging.

You'll want to replace Adblock Plus with uBlock Origin. Faster, more powerful. It can also replace NoScript, though the UI isn't as well tuned.

If you stay with NoScript, you won't have to do anything to get the new version.

All old themes will be dead; there will be a bunch of new themes.

A basic session manager is built in, Tab Session Manager might be more useful for you.