If someone is playing Food Chain.dec and has no back ups, a resolved Opposition Agent that steals the food chain has now completely stolen their chances of winning
Flexibility, X spells, mana reliability, blah blah blah
Its survivability means itll stick around until you can drop a Sporesower Thallid or Sporoloth Ancient to kick it into high gear
Kataki, War's Wage and Gorilla Shaman are examples of some cards that deal with a lot of artifacts
Chandra, the Firebrand 3.5 This is reds best planeswalker being cheap and versatile complete with a self protecting mechanism
As a 4/4 flyer with infect, it can stack up poison on a single opponent fast, especially combined with his cheap haste-granting ability, particularly useful when Skithiryx is rising from the command zone multiple times a game