Flux slowed me down at the start, but React was rather easy. Easier than Ember for example. The API surface is tiny, everything is done with components and the composition of them.
Flux on the other hand was hard to grasp, since all of the different implementations and the naming problems. Actions in MVC are just methods of the controller classes, but in Flux they are objects, which kinda threw me off track right in the beginning.
Also, I came from ExtJS and Ember and was accustomed to two-way data binding and the whole Flux thing felt backwards, because interacting with the Models in Ember-Data didn't take any effort. After they were bound I just needed to type my data and they get updated automatically. I just had to look about gathering them at the end and send their updates to the server.
But I didn't choose it. Another dev at the current project did.
It took me a few weeks to fully understand what Redux is about.
I didn't know about "one store for all", the difference between actions and action creators and how immutability was mandatory.
I just jumped in and started my first component with a (rather bad) tutorial I found with google and copied a Redux store and actions from a co-worker.
The Redux docs weren't good till 1.0
After I asked Dan something I realized I got it all wrong. But now I think it's a really nice way to do front-ends.
The recent Ember 2.0 roadmap suggests a more React-like workflow with an emphasis on components and HTMLbars driving the bulk of the framework. It still has all the lovely two-way data binding but it's complimented with a more fun workflow for writing the view code. I like Ember Components because they marry the best parts of the upcoming (and exciting, but disappointingly slow-to-market) Web Components with a workflow similar to React.
Flux on the other hand was hard to grasp, since all of the different implementations and the naming problems. Actions in MVC are just methods of the controller classes, but in Flux they are objects, which kinda threw me off track right in the beginning.
Also, I came from ExtJS and Ember and was accustomed to two-way data binding and the whole Flux thing felt backwards, because interacting with the Models in Ember-Data didn't take any effort. After they were bound I just needed to type my data and they get updated automatically. I just had to look about gathering them at the end and send their updates to the server.