In the first example, you are just inheriting amitBaseClass prototype.
function SomeClass() { } SomeClass.prototype = Object.create(amitBaseClass.prototype);
In the second example, you are executing the constructor function. An instance of amitBaseClass is created and you are inheriting the who complete amitBaseClass object.
function SomeClass () { } SomeClass.prototype = new amitBaseClass ();
So, both are doing separate work.