i think they are just trying to catch up version wise to Chrome and Internet Exploder.
People think that chrome and Internet Exploder must be better than Firefox because they have higher version numbers. TBH, to a certain extent they are right. not sure about internet Exploder because i use IE 9 for 2 hours and then uninstalled it.
Chrome or Iron in my case is a different kettle of fish, it starts up super quick, it load pages super quick, it don't crash any where near the amount of time Firefox 4 does.. the best thing is that if I update Iron, the plugs ins I am usinf still works, something that Firefox seems to have problem with.
i still got FF3.5 installed, and I do use it for some stuff, but iron is my main browser.
Desktop machine now powered by windows 7 pro 64bit , laptop by ubuntu
On ADSL24 using C&W network.