I was a pretty die hard FF user for years. I don't even remember why I made the switch to Chrome a few years ago. I think it was during a period when FF was going long stretches of time without updating, and I was frustrated with bugs that weren't being addressed. After I switched to Chrome and realized how lightweight it is in terms of system resources used, I was hooked. As someone who frequently keeps 75-100+ tabs open at all times, an efficient, lightweight browser is a necessity!