I am not working on any framework, but I guess you meant "working with".
I am currently working with vanilla WebComponents. Add a bundler, TS, SCSS and handlebars to the mix, and the result comes close to any of the frameworks above, however, is un-opinionated and only uses libs, which I then can employ for cases I see fit. For example, an average custom component lives in a folder composed of three default files, which can be imported and bundled, but could be split up in any way or left out if not required:
src/
MyCustomComponent/
index.ts
layout.hbs
style.scss
The reason for the decision is that we can easily upgrade these libs - mostly with minor to no work, however, with frameworks, every major update can break a lot and might mean converting a lot of code. To be fair, there are a lot people at my place who had to rewrite entire code-bases because of the Angular 1.x -> 2.x upgrade.
Personally, I'd like to re-visit React. It seems it's in high demand right now, and knowing other tools is always a good thing. In my opinion, it might be a nice alternative to handlebars in the above setup.