People consider Firefox as one of the best browser. Cyber crime is at its peak though. Some crypto extensions are never scanned for malwares before making them available for internet. Recently, chrome acted upon some crypto extensions and removed such malwares. FF is learning.
I don't know who is considering fire fox as the best browser, in what aspects is fire fox the best browser. For me I am interested in a browser that is secure, and support anonymity, and Tor browser is ahead of fire fox in that regards. But know that you also contribute in getting attacked by malware. You can't just keep visiting any random site and expect not to encounter malware.