New 100% promise-driven data models. Here's a sample of how the controller changes.

data.js

// in the old data model, you had to do a bunch of crufty bullshit

$scope.messages = Messages.all();
$scope.$onRootScope('messages.updated', function() {
    $scope.messages = Messages.all();
});

// ew, what's even going on there? Well, it loads the data from the Messages service,
// but then has to wait for an event to make sure it actually updates when the data changes.
// Like a peasant.

// Here's the new syntax:

Messages.all().then(function(res) {
    $scope.messages = res;
});

// it asks the Messages service to give it all records, and if they don't exist
// it will fetch new records from the server. It then returns a promise that will
// always update when the records change.

// Oh, you want to save some data? Make a new message? Here:

$scope.newMessage = {
    message: 'This is a new message',
    email: 'myfriend@gmail.com'
};

Messages.save($scope.newMessage);

// BAM. It's that easy.