I swear, I don't know which choice is safer. In theory, going with Minwook would be wiser, considering the current Woojoon is literally an alien wearing Woojoon's skin. On the other hand, if she chooses Minwook, there's a good chance Woojoon will go on a rampage (we still don't know whether he has any powers). So, yeah, she's damned regardless of whom she picks. Woojoon is simply a ticking time bomb.
On a related note, Minwook is quickly becoming my favorite male lead when it comes to this kind of story. Dude's an absolute treasure. If he doesn't win, I hope he will at least find someone worthy of him in the end. He deserves a good ending.