When you force your opponents to make a villainous choice, they will be forced to choose between two options, each one benefiting you
An example is Copper Host Crusher, a terrifying Phyrexian monster that any green draft deck would want
But unfortunately, these numbers do not mean much to me for a couple of reasons: First, I (and most of you) can't get StarCityGames or TCGplayer Mid prices when we sell our cards (wouldn't that be nice?)
Even if you tap a creature to completely remove the generic mana cost, harmonizing is usually more expensive than casting spells the old-fashioned way, and besides, that tapped creatures could have done something else
My ranking: Kinda Fun Cleopatra, Exiled Pharaoh I love Golgari, so I might be biased, but a Golgari legendary sacrifice deck seems incredibly fun
It's also great in a fetchland format as it gives you a versatile mana dork that can swap to one that affects life totals