Honestly the big one for me is being able to finally debug async code, which Chrome has been able to do for a long time, and FF simply couldn't. As someone who

Honestly the big one for me is being able to finally debug async code, which Chrome has been able to do for a long time, and FF simply couldn't. As someone who uses FF as main browser, not being able to use to for modern code and being forced into using a different browser for proper debugging has been quite frustrating.