I don't know what the fascination with Cap is. It is either the nut high or it blows.
This is completely true. Usually, in fact, it blows. I don't believe I'm going to play with Jester's Caps in the future in the MD. If I do, the field will have to be just right for it.
I don't understand why everybody and their grandfather is now running Jester's Caps. I did it because it was a brilliant idea for the Richmond metagame. I expected Combo, Gifts, and Stax. Jester's Cap is obviously broken against the earlier, and not that bad against the latter.
I also trusted Yespuhyren when he said the card was good against Slaver - all you had to do was take their Slaver and two randoms and they had a hard time winning the game. Obviously, neither of those are the case, but it seemed like a good idea at the time.
The simple fact is - Jester's Cap is among the more difficult cards in the deck to hardcast (4 mana isn't hard to come by, but it's not easy either), and it's two-mana activation cost makes it okay, but it forces you to not run Null Rod, which can be better against both Combo and Gifts.
While Jester's Cap can randomly win you the game (well, maybe it's less random then I'd make it out to be), there are better alternatives that will absolutely win you the game.