believe is completely impromptu + visual (when you change the corner right in front of the spectators' faces) + your angles are about 98% safe and tnr requires a gimmick and some angle awareness but the ending is killer.
Joel Paschall teaches u in depth about the psychology of the effect and the sleights of hand. He teaches you how to clean up so that you are 100% clean. Plus, he teaches another method of believe he likes to do which requires a bit more sleight of hand.
chris K. shows you how to make the gimmick of TnR which is quite creative and out of the box (credits to Mathieu Bich). He teaches you a routine you could do with the gimmick. Plus, he tells you different ways of performing it (i.e. as just a color change, or just a torn and restored card: the color change is optional.)
Think about which one you would rather do.
I personally liked Believe more due to its impromptu-ness. it is a simple trick, but packs quite a punch, and it requires some skills in sleight of hand.