Contrary to what was said in class today, NYのちかてつはべんりじゃありません。 It is an unpredictable hellhole. (Upcoming dilemma: will it drive me to Murray Hill, or will I bite the bullet and live elsewhere?)
とうきょうのちかてつはすてきです--if you're short. I thought Paris, DC, Rome, and Vienna were ok; London and Prague were adventures. Brussels, Lille, and Seoul were pretty good. I still think that riding a subway is like being in a sci-fi movie--the subway is a marvel of human ingenuity, but more dystopian than not.