I had to switch to Chrome after Firefox caused my computer (macOS Mojave, 2012 MBP Retina) to freeze to the degree of requiring restart every few days. Even when it didn’t freeze the entire machine, the browser itself would lock up a few times a day. During the course of normal use, my CPU temps would jump to 100°+ from a baseline of ~55°. (And battery life was disappointing, as other comments have noted.)
These issues occurred when my computer was plugged into a charger or on battery power. Replacing the thermal compound, thoroughly cleaning the fans, and reducing the number of open tabs and windows didn’t resolve this. Chrome doesn’t appear to cause these issues on my machine, holding all other workload and plugins constant.
I really want to use Firefox but cannot rely on it currently.