First, the justification for comparing them. They're both enchantments, both rares, and they're both new issues for M14. They rate #79 (Into the Wilds) and #85 (Dark Prophecy) overall on Bestiaire. They also both offer a form of card draw.
Another thing that they both boast is exceptionally appropriate flavor for their colors. Green's card draw is always based on creatures or lands, and black usually has a life cost for its card draw. So, both of them have that going for them.
At their cores, Dark Prophecy is a stronger card. Even with the life cost of losing creatures, nine times out of ten the card draw is going to be well worth the loss. It also opens up some profitable situations, like trading a Child of Night for a Coral Merfolk or Goblin Shortcutter in combat. While sometimes you're worried about pinging yourself to death, in general you're going to want to have the card.
Even still, Into the Wilds is a more playable card. It's got the lack of a downside which is nice, but the real value is in the casting cost. Dark Prophecy is basically unplayable except in a mono-black deck; in any other situation, you're not going to be able to get enough value by the time you cast it. Into the Wilds meanwhile will always get a little work done. It's not a bomb by any stretch, but it's perfectly playable. I'm actually pretty surprised that Dark Prophecy gets taken as high as it does. I guess with Bestiaire you don't actually have to play the deck, so you can be a little more loosey-goosey. But for me, this one's not close.
Joe's pick: Into the Wilds