Mirror of Truth or Darkmoon card Death?Follow

Guys, which trinket should I be using for PVP (muti spec). Mirror of Truth, or Darkmoon: Death?

Darkmoon seems to proc a lot at the beginning of a fight (like 50% of the time on a test dummy), so I'm leaning more towards it......but I was wondering if there was an established opinion up here on this?

Thanks....I thought so.