During the Keynotes when Steve Jobs would show off the computers they'd run their Photoshop or really large Excel file tests to show just powerful their chips were. If I remember right, all of those tests were highly selective. For most regular computing tasks, I felt like PC's were faster.
In marketing, if you're in second place it doesn't hurt many times to attack first place. In the consumers minds, you're putting yourself on similar footing to the first place contender and then getting to highlight specific differences that make whatever case you want.
It many not be elegant but Amazon's promotions and Samsung's recent phone ads do illustrate differences between the products. They may not be the most important differences to a lot of people but the burden is on Apple to show that, not on competitors to follow a vague sense of fairness.