Ranked in these QuestionsQuestion Ranking
Pro Plugins for popular IDEs
Telerik provides Visual Studio and Sublime Text plugins for the AppBuilder.
Pro Integrates with Apache Cordova
AppBuilder offers a fast way to import Cordova plugins such as the camera.
Pro Allows you to develop native apps
Pro Backed by Facebook
Facebook writes their mobile apps in React Native so the code base gets pretty thoroughly used in some highly demanding scenarios.
Pro More predictable control of the state
The one way data flow, makes it more predictable and easy to control.
Con Young project with a small community
AppBuilder is a young project that's been fairly slow to gain popularity. This means the community is rather small, so there is a limited amount of 3rd party learning resources available.
There is a forum, but it's not very active.
Con Steep learning curve
Con If core team doesn't use a certain feature, it's not developed
Whenever there's functionality you need that they don't use in their apps, it's not going to get developed by them, even if it's obvious it should be in the core. They always say to either submit a PR or create a separate module.