Heideggers Interpretation of Kant : Categories

Is there any justification for Heideggers famous violence against Kants philosophy? An independent assessment of the worth of Heideggers argument is also made all the more pertinent by the evident misgivings Heidegger had about his interpretation of Kant. We must ask of Heideggers interpretation of Kant: 1) Is this good Kant? and 2) Is this good Heidegger?