Ember.Array

This is an abstract implementation of observer-friendly array-like behavior. Concrete implementations are expected to have implemented methods, such as length() and objectAt(). Notable convenient methods are any(), every(), filter(), filterBy(), find(), findBy(), forEach(), getEach(), map(), mapBy(), objectAt(), replace(), reverse(), sortBy, without(), and so on.

Ember.ArrayProxy

ArrayProxy wraps objects that implement Ember.Array for binding use cases and swapping content while iterating.

Ember.MutableArray

This is an extension of Array, supporting an array of ordered sets.

Ember.Enumerable

This is a mixin for enumerating arrays.

Ember.NativeArray

This is the most concrete implementation of all of the above. You would use this in most cases.