According to Tom's Guide[1] Microsoft Edge beats out both when it comes to RAM utilization but Chrome just edges out Firefox when loading >10 tabs. That was in 2021. I'd be interested to see any other comparisons or benchmarks.

1. https://www.tomsguide.com/news/chrome-firefox-edge-ram-compa...

It took a lot longer for Firefox to get GPU accelerated video playback on Linux iirc

Perhaps a "niche" use case for some, but there's a lot more Firefox users on Linux in particular