Developing with 3a2

I plan on using AnsPress for my latest website, but I need to make some modifications to make it fit my wishes. I’m wondering if 3a2 is stable enough to develop with, or if I should wait for 3 beta, or even the full release of 3, before I start modifying it to fit my wishes.

Basically what I need to know is: Will a lot of things change from 3a2 to 3.0? Or are they mostly bugfixes and the like?