a .0 or .1 release will usually have more bugs than a .2 or a .3 release. If someone upgrades from 3.x today, the choice is upgrading to 6.4 or 7.1
7.1 has more features and a nicer user interface, but is less stable than 6.4. It's up to the user to make that trade-off.
There have been thousands of commits this summer: