About five years ago, those types of cards were much better since cubes were slower, but with many cubes adopting aggressive strategies and getting more efficient removal options, things like the Vindicate test (where you get an effect out of it if the creature dies at sorcery speed, so Consecrated Sphinx passes that test) hamper its effectiveness, but it does protect itself well if you are able to untap with it since you can turn just about any blue card into a counterspell or draw card
Speaking of #6 Zephyr Spirit (Ravnica) Why is it bad
it doesn't matter how much a permanent costs to cast, just how much colored mana
2009-02-01 If multiple effects modify your hand size, apply them in timestamp order
It has a low floor, but a very high ceiling where if the right spell is copied, it could be game-winning
It depicts an angel flying above the clouds and into either the night sky