The most common complaints are about UI refresh performance in a React-Redux app, particularly if you're dispatching an action for every keystroke in a text input. The original post we're commenting on covers several aspects of good performance, and my other comment in this thread at https://news.ycombinator.com/item?id=14706509 has links to benchmarks and more info on various performance scenarios and optimizations.

I wrote the post because I've seen complaints on community chats. Lots of things that seem obvious to you and me aren't obvious to others :)

No to all questions.

An app that uses redux poorly becomes slow. Naive devs then claim redux makes their app slow. Propeelu using reselect solves a lot of the problems.