I use AngularJS because it was back in the days one of the interesting and most hyped frameworks. Especially the two-way databinding and the amount of free angular-components from the community made the development of this research project very easy and fast. React on the other side, was just on the geginning of its rise and Angular promised a more SPA approach, also with HTML & CSS templating, which I had experience from the past. React with JSX was too new for me and a bigger overhead, so I tried AngularJS. Today with no backward support of Angular 2.x/ - /8.x, I personally switched to Vue.js as it shares many concepts from Angular & React and is easy to learn.