Which is better NGRX or NGXS?

Akita is a state management pattern, built on top of RxJS, which takes the idea of multiple data stores from Flux and the immutable updates from Redux, along with the concept of streaming data, to create the Observable Data Stores model. Akita encourages simplicity.

There are several great state management libraries out there to manage state in Angular : E.g. NgRx, Akita or NgXs. They all have one thing in common: They are based on RxJS Observables and the state is stored in a special kind of Observable: The BehaviorSubject.