I actually use Edge as a daily, but I also use Firefox because I want to support them. Unfortunately, Edge and Chrome are superior to Firefox in performance. Edge especially is really really great at resource management, and it doesn't matter if I have 1 or 700 tabs and windows open. It'll manage it without any issues. Firefox however, won't. Sure, it's rich in features and it's very very flexible, but it's not as stable or fast as the former.