JavaScript inheritance: Object.create vs new

In JavaScript what is the difference between these two examples:

Prerequisite:

function SomeBaseClass(){
}

SomeBaseClass.prototype = {
    doThis : function(){
    },

    doThat : function(){
    }
}

Inheritance example A using Object.create:

function MyClass(){
}

MyClass.prototype = Object.create(SomeBaseClass.prototype);

Inheritance example B using the new keyword

function MyClass(){
}

MyClass.prototype = new SomeBaseClass();

Both examples seem to do the same thing. When would you chose one over the other?

An additional question: Consider code in below link (line 15), where a reference to the the function's own constructor is stored in the prototype. Why is this useful?

https://github.com/mrdoob/three.js/blob/master/src/loaders/ImageLoader.js

Excerpt (if you don't want to open the link):

THREE.ImageLoader.prototype = {

    constructor: THREE.ImageLoader
}