While it can be effective in certain situations, there are arguably better options like Rule of Law or Eidolon of Rhetoric that have similar effects with additional benefits, making them more versatile choices in competitive play
And while that's also true of the Archangel, the Archangel is many turns away and, when we finally could can slam it onto the table, we won't have any extra mana for casting Prey Upon
Like most Magic: The Gathering cards, the value of Sauron, Lord of the Rings depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Tales of Middle-earth Commander)
However, all of the different card types, effects, and strategies can look pretty intimidating when players are just starting to learn about the game
For as long as it remains exiled, that player may cast it as a non-Adventure spell
Basically, you do no damage just to give your opponent a 50% chance of pummeling you instead of a 100% chance