1.speed - FF tools always take time to open a script file. Chrome hickups only for huge files which is understandable.
2. Sourcemaps doesnt work most of the times in webpack bundles. Dont know why. (Maybe they tested only for chrome or something.)
3. This new FF devtools was developed after chrome took the dev mindshare and familiarity. I don't see FF devtools very compelling to be used all the time. No disrespect, but there is no incentive or visible improvement in productivity.
4. I'm a react dev now, the react dev tools plugin in FF is laggy. Not pleasant to use.
I can go on like this. But maybe for your use case, FF devtools is better.