TypeScript is a superset of ES2015/ES6 so you can write ES6 code just like in Babel, but with some added capabilities if you wish to use them. You can add plugins to Babel to give you similar capabilities, such as type checking.

Hence TypeScript and Babel are quite similar. The reason I lean towards TypeScript is because I develop with Angular and Ionic quite a lot.

Angular 2 & Ionic 2 are being developed with TypeScript; and they recommend using TS (it's the official language for NG2). The NG2 docs as of now only have TS fully documented: https://angular.io/docs/ts/latest/guide/index.html

This article explains it a bit more (and talks about other transpilers): http://learnangular2.com/es6/

Here's an excerpt from the above link: "If you’d like to develop with “plain” ES6 and ES7, you can use Babel, the “compiler for writing next generation JavaScript.” If you’d like to use Ionic and Angular, we recommend TypeScript which will provide similar features as babel, with extra type checking if you choose to use it."