Admittedly, my own experience was with older versions up to 57, but what it felt like e10s did not really help with responsiveness, especially after very long sessions (24 hours+). Restarting Firefox used to be a daily ritual (with all the lost website state that entailed) as JS pauses started becoming very noticeable. Fx would also keep the CPU in high power states with constant 10-20% CPU usage near the 24 hour mark.

I don't know if it's an architectural limitation of how e10s was implemented, but Firefox still feels like a single-process browser. On the other hand, Chrome remains responsive even after a week of being open.

Thanks for offering to take a look! What is your email? Next time it happens I'll be sure to send the logs along.