Anybody who adopted Angular right out of the gate is kicking themselves now because everything they wrote in the last year is now obsolete. Hopping on the latest thing might be fun and you might learn a few things, but I'd prefer to wait for things to be fully battle tested and have a good history of support before I put it into production.

Another good reason is speed. It's rare for a framework to be faster than native DOM api's. And the app loads faster!