Containment Priest is strong against Show and Tell, exiling Atraxa, Grand Unifier or Acererak the Archlich when they try to put it onto the battlefield instead of casting it, which blanks that half of their plan. It does not stop Aluren, since creatures cast through Aluren are still cast, so keep Witch Enchanter in to destroy Aluren, Omniscience, or Lotus Petal. Anointed Peacekeeper is a weaker tax effect against a deck full of redundant payoffs, so it comes out for the Priests. Chalice of the Void at one stops Ponder and Brainstorm, which is a huge tempo hit, but it does not stop Lotus Petal, which has mana value 0.