Who said you only have to use one browser? I have all 4 installed and use what ever one I feel like at the time. Internet Explorer, Edge, Chrome and Firefox are all good. Each has its advantages and disadvantages. None is that much better than the other.
Yes, thank God for being able to do that. I have Firefox with multiple profiles (for 64 bit, change your shortcut address to "C:\Program Files (x86)\Mozilla Firefox\firefox.exe" -no-remote -p [with the quotes. For 32 bit leave out the (x86), plus Pale Moon and Chrome, IE and Edge.