I've been loyal to Firefox for a long time - but they are testing me to breaking point.
First they made it impossible to use Selenium - so I moved that application to Chrome where it works well on built-in support.
Then recently W7 Firefox 54.0.1 32bit regularly keeps locking up or crashing. That has never been a problem in the past. The crash reports get sent off automatically - but I've no idea if there is a common problem.
I will have to start looking at alternatives to Firefox (not Chrome or IE) for my general browsing. The Palemoon reference above sounds interesting.