I have NEVER had a problem with Firefox and I use it constantly. I like all the add-ins it has available so much better than IE. I used Opera before and it's ok but I still prefer Firefox. However, this is just an observation. I have noticed that Windows computers and their apps slow down over time. And the only solution is to wipe it clean and do a fresh install. I don't have this issue with my Mac
ShayD probably knows the technical reason for this. But the shop that's been working on my on my WinTel boxes for years describes it as "Microsoft Bloat"... like it's a disease or something. Depending on how much surfing you do on a given machine, over time, it's like a person who eats fatty foods and eventually their arteries get build-up. Pretty neat description, I thought. And yeah, the only "cure" is to wipe the damn things down periodically.
Anyway, I stopped using IE about two years ago... and I think my blood pressure went down about that time too. I alternate between Safari and Firefox now. I like them both. But FireFox has many more features. Though Safari (until this last upgrade) seemed to be faster. I've heard good things about Opera. Maybe I'll try it too.
I try to restrict online banking, brokerage, etc. to one computer and general surfing to another. But security, viruses and malware really concern me on all of them. So whatever browser I use, security is a KEY element. With the recent updates, I need to see which ones are ranked highest now. But speed means less to me than security. And some of these off brand "hobby" browsers just seem like things that I wouldn't want to fool with. Much like Android phones, they may have some neat features. But the "open" platforms sometimes invite bad people who enjoy doing bad things.