Using callbacks in a Restangular service
Well, when you're already using promises you also just return that instead of using a callback.  Then you can also chain more promises at the end and add error handling.  Other than that it looks fine; I don't see what you'd really change there.

myApp.controller('CustomerController', ['$scope', 'Teams', function($scope, Teams) {
    Teams.getList().then(function(results) {
        $scope.teams = result;
    }, function(error) {
        ...
    });
}]);
myApp.factory('Teams', ['Restangular', function(Restangular) {
    var Teams = {};
    Teams.getList = function() {
        return Restangular.all('teams').getList();
    };
    return Teams;
}]);


If you want to get rid of Teams, I've seen this variant as well:

myApp.factory('Teams', ['Restangular', function(Restangular) {
    var getList = function() {
        return Restangular.all('teams').getList();
    };

    return {
        getList: getList
    };
}]);