If you install Firefox from the tarball, it a) doesn't require root permissions and b) autoupdates in place, so I think it's easier to install and upgrade than

If you install Firefox from the tarball, it a) doesn't require root permissions and b) autoupdates in place, so I think it's easier to install and upgrade than if you got it from a .deb. (Chrome's .deb includes configuration to add Chrome's apt repository; I'm not sure if Firefox's does.)