Nissa, Vital Force looks to be a classic sideboard card for midrange decks, as her plus ability is great at putting pressure on an opponent and the minus is useful in returning another threat from the graveyard
Both are distinct from ability words, which only label certain kinds of abilities for flavor rather than directly representing their rules text, and which cannot be referenced by game mechanics
Sure, its powerful and will give you a lot of extra value, but Id much rather get five, six or even ten cards from this list before buying just it alone
Responding to these concerns, head designer Mark Rosewater took to his Blogatog blog to answer some questions about Double Feature
Power Artifact ($190) If you see a card that cares about artifacts on this list, you know its busted