Pointed Discussion

so good against jub jub

At Times It Can Be Better Than Cancel And Sometimes Much Worse

Should have been named "Double or Nothing"

More splashable than Cancel but not nearly as reliable.

This is an interesting card. While not at all reliable, it scales to the size of the threat. The bigger the spell, the bigger the challenge it is to overcome Rethink.

I'm not sure it's playable, though. If others know you're playing it, on the other hand, they might try to leave open twice as much mana as they need for things, slowing them down significantly for the rest of the game (whereas something like Mana Leak would only slow them down towards the beginning of the game).

...So basically a hard counter?
Of course, using this against any of the Pacts results in some of the most hilarious moments in gaming ever. "Are you sure you wanna cast that, hmm?"

Not the most reliable counterspell, but it has it's place in formats like EDH, where most threats have a much higher CMC, thus increasing this cards usefulness, I suppose.

The fact that Cancel costs makes this much worse. Sure, it's slightly more splashable, but it is much less reliable. It's optimal against people who tap out to play spells, but can be a dead card in your hand against lots of kinds of decks.

I quite like this card, unless you're announcing to everyone it's in your hand no one really expects it. In EDH it's amazing