If your project does not have a desktop version requirement, I’d suggest using Ionic 1 and specifically the Ionic Creator. It looks really easy to get up and running quickly and looks very stable. The weekly videos that @mattkremer puts out are really cool.
However, if your project needs to run in a desktop browser as well, Ionic 2 is the way to go. I’ve been prototyping in Ionic 2 / Angular 2 for months now, with a release plan of around a year from now. The upgrades from beta have been a HUGE pain, but the new stuff is a tremendous improvement. While there are still some missing features (a datepicker that defaults the selector to today) and development environment issues (slow dev builds), the code itself feels ready for prime time.
Ionic 2 is extremely cutting-edge. There are absolutely some risks in using this right now. However, everything the Ionic team is doing is building my trust in their platform. I do wish they could do it a little bit faster, though.