Sorin Markov's +2 ability drains life, but he also sets one of your opponent's life total to 10
The one life loss is negligible, and even beneficial in some decks like Vilis, Broker of Blood
It can be effectively played in mono-black control or Rakdos decks in Pioneer or in the popular Grixis control decks in Standard
Whether my characters then challenge, quest or do nothing depends on the board state, but I always like to use all of my ink in the early turns on characters - they give you gameplay options and allow you to get ahead
I believe if new decks are to going to rise in the tiers of the RotF meta, they will be built around these engines, so before you simply bow to our active draw overlords, explore what being passive may net you!
If an affected permanent changes controllers before its old controller's next untap step, this ability will prevent it from being untapped during its new controller's next untap step