I have used knockout, angular, react for a while. When I used vue.js the first time, I smiled. It made me happy.
I like vue.js, the only and biggest concern is that it is a single developer project, I'm deciding between react and ng2 now because of that concern, leaning towards react right now.
Evan has added a dozen collaborators to Vue team. so it is no longer a single developer project.
Yes, the majority of code is still written by Evan, due to speed required. but we know that vue is heading in right direction.
I like Vue.js, but there are no good UI frameworks such as Ionic that work with Vue for mobile apps.