Knockout vs Marko

Knockout uses HTML5 data attributes to bind HTML elements to data objects in javascript. This allows more work to be done by the framework rather than requiring you to specify where data should be bound in the javascript. The data binding is very intuitive as the bindings are done within the HTML itself in the location it should be bound.

Has a low entry barrier and an easy learning curve. It's especially easy to learn for beginners.

Bindings in Knockout can also be used to control the generated structure of the HTML. There are bindings provided to allow for iteration and conditionals. The structure of the html reflects the structure of the data so iterative elements are bound to arrays in the data model. Having the HTML structure maintained by bindings keeps the templating simple, easy to read, and maintain.

Knockout also allows for string based templating so you can use whatever templating library you prefer.

Supports a large number of browsers, including IE6.

The excellent tutorials with built-in exercises are a great learning experience, even for people without prior MVVM and data binding experience.

Models in Knockout can be watched to keep the page data up to date by using observable objects. The observables notify Knockout when data is changed and automatically updates the page when this happens. By having Knockout maintain this relation, it keeps the front end code cleaner and simpler, and by enforcing a consistent pattern with observables the methodology can be more robust.

One can do a lot of things and it keeps self references and other types of loops under control.

Knockout does one thing, and does it well. It doesn't try to take on more than one area. It does MVVM data binding and that is it.

Using components is a great way of breaking up large modules into simpler ones.

Marko consistently outperforms other alternatives in code benchmarks, both on rendering speed and compilation time.

Custom tags provide a simple mechanism for embedding more complex components into a template by extending the HTML grammar with support for new tags. For example:

<div>
    <say-hello name="World"/>
</div>

Custom tags are easy to create since they just map to a JavaScript "renderer" function as shown below:

module.exports = function sayHelloRenderer(input, out) {
    out.write('Hello ' + input.name + '!');
}

Custom tags support nested content:

<fancy-overlay title="My Title">
    This will be the body content of the overlay
</fancy-overlay>

Custom tags can also have parent/child relationships to support more complex use cases such a "tabs" component with nested "tab" components:

<fancy-tabs>
    <fancy-tabs:tab label="Home">
        Content for Home
    </fancy-tabs:tab>
    <fancy-tabs:tab label="Profile">
        Content for Profile
    </fancy-tabs:tab>
    <fancy-tabs:tab label="Messages">
        Content for Messages
    </fancy-tabs:tab>
</fancy-tabs>

Streaming allows progressive HTML rendering and reduces time to first byte.

Marko supports both server-side and client-side rendering.

Marko Widgets allows UI components (rendering + behavior) to be built using Marko.

Avoids ugly globals and "named" templates.

var template = require('./template.marko');
var html = template.renderSync({name: 'Frank'});

Marko makes additional asynchronous calls after the view rendering has begun.

Easy Integration with Express and Node

The documentation is extensive and very helpful. It also contains several sample applications which are very useful.

JavaScript expressions can be executed inside the templates.

Marko has a HTML-like syntax which should be easy to read and understand for everyone who has even minimal experience in web development.

It is easy to get up to speed and understand what is going on in a very short period of time.

Marko's compiled templates are usually very small, as proven by benchmarks.

To prevent regressions, Marko includes a full suite of tests. The testing harness renders a collection of templates and does an exact string comparison to make sure that the tests rendered exactly as expected. There are also API tests, and negative tests to make sure that errors are reported in a friendly way.

To run tests:
git clone https://github.com/marko-js/marko
cd marko
npm install
npm test

Error messages come in an easy to read and friendly format, with valid stack traces and file formats of the file(s) which brought the error(s).

The Concise syntax type lets you write Marko with a Jade-like indentation based syntax, and the Mixed mode lets you combine in regular HTML-style syntax.

Marko's development community is rather small compared to other frameworks but community is well mannered and active. You can chat with the core development team using gitter.im