Hmm...
Me vs Dapper Luna...
Depends, where are we fighting? Her world; where she's basically God's sister with almost as much power in magic, where she can also fly and doesn't seem above causing widespread chaos and destruction when things don't go right for her?
Or our world where she's a funny looking horse?
Who am I kidding? It doesn't depend on anything. I can't fight, I'm too big of a pacifist. I'm dead.