Depending on which family or work computer I handle, I use IE, Firefox, or Chrome. I have been using Firefox for years and prefer it over IE. I prefer Chrome over IE too.

I can't use Firefox on my work PC, so I use IE and Chrome. IE is required for the work intranet. Chrome is for personal use.

On my home PC I use Firefox. Chrome is faster than Firefox on some sites, but not all. I also like using add-ons, so Firefox wins on that.

I use Firefox on my smartphone. Anything is better than the phone's default web browser. I also like how I can synchronize the Firefox bookmarks my home PC with Firefox on my smartphone.