Of course Redux today is the most popular solution for some reasons, but is suffers from excessive, unnecessary complexity compered with MobX which is more simple, intuitive yet powerful.

I use baobab and I hook it to react with baobab-react

Depends on what is being implemented.

I have small toolkits which didn't have a need for state of the art stuff. So I just let it be in a Parent Container. Otherwise, I take a pick from Redux or MobX if it is a long maintainable project in consideration.

My 2 paise.