It is much better and more powerful than the native angular, I will make a basic comparison:

ngRoute

• Routing based on url
  • That is, only one route per screen and one controller for it
• Does not support multiple routes
  • All html should only have a <ng-view> tag, if you have more than one, Angular will inject the same content inside all
  • If a <ng-view> inside another, there already was, will generate recursion

Ui-Router

• States based routing
  • That is, the URL is just a routing tool and not a delimiter
• Supports route, multiple inheritance and views on the same screen
  • You can by two <ui-view> tags on the same page and inject a template with your own controller in each
  • You can also place%% of% within the other for routes within routes without problems, and having total control of the content injected and behavior of each one

Implementation

It's very similar to <ui-view> :

app.config(function($stateProvider, $urlRouterProvider) {

    $urlRouterProvider.otherwise('/home');

        $stateProvider
            .state("home", {
                url: "/home",
                templateUrl: "home-template.html",
                controller: "HomeController",
            });
    });

See also

• 8 things you need to know about AngualrJS - the first is just about Ui-Router
• AngularJS Routing Using Ui-Router - Tutorial very nice for you to see the potential of this tool
• Using Ui-Router - Content of a training related material I gave on Angular + WebAPI