There have been very few noticeable changes from version 4, to 5, to 6, to 7 beta, which I'm now using. The version numbers are meaningless to the user and most won't notice any changes on the surface. Even all my add ons are all working exactly as they did 3 versions ago. The new release schedule is to get security and bug fixes, as well as new, tested, features out to the users quickly. No more waiting a year as we did for version 4
Google has been doing the exact same thing with Chrome all along and most users haven't noticed it. My Chrome is version 15