I think that the main thing you need to remember in everything you submit -- personal essay, post-sec experiences, secondaries, etc. -- is that you're trying to give the adcomm a more complete picture of you. Therefore, start thinking about this question in terms of what learning experiences are best for you. Are you the type of person that does well in a smaller, closeknit student body? Do you learn better in environments that stress teamwork over competition? Do you excel in high pressure situations? A little introspection about the environments where you do your best thinking/learning will help you identify what's best for you. Describe learning situations that you think are your most successful, and then explain (based on your reseach) how X school's pedagogical atmosphere supports your own learning style. The essay's focus then shifts from a regurgitation of the school's website (which you already know isn't unique) to a little more insight into what makes you tick.
Good luck!