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.
If so, what about it is slow? And slower than what?