It is amazing. I think there's not a single other artist who's work appeals more to me than Escher's.
The pure esthetics and impressive geometrical forms combines fine art with the mathemathical rules of nature and he does it in such a convincing way that it moves me. Not with emotions, but with a sense of perfection and utter esthetic beauty which my mind is barely able to handle.
He's one of the most under-appreciated artists I think.