Kind of a psuedo-draw for red. You only get one
turn to try and play what you get off of it, so
make sure you have a decent amount of mana to
cast the Act as well as whatever you might flip
from it. In a red aggro deck where little costs
more than three anyway, this would be a solid
draw card once you've played out your hand. The
fact that it can effectively "skim" excess lands
off the top is helpful too, and all the more
reason you want to wait until you've got mana to
spare.
It's the red Divination! Except that you can't
just run it out there on turn three, or to use
up any spare mana you might have. Then again,
you don't always do that with Divination either.
Sometimes, late game when you have a lot of
mana, the two cards won't actually play all that
differently; I can't think of a common situation
where the fact that Act on Impulse's extra cards
don't go to your hand first will be relevant (Maro
perhaps?). And in most red decks, I'd be
surprised if you were ever drawing many cards
that you didn't want to play right away.
Today's card of the day is Act on Impulse which
is a three mana Red sorcery that exiles the top
three cards of your library and until end of
turn you can play them, with casting costs and
other requirements still in place. This is
a situational card that isn't likely to see much
play as it requires a decent supply of mana or
very low cost options to cast from the exiled
choices. With five or six mana it
can potentially play all three cards,
particularly if one is a land and none were
already played, which gives it potential value.
Overall the three mana cost, non-instant speed,
and comparisons to Blue's much better draw
options will be seen as outweighing the possible
card advantage of using it.
For Limited this is impractical in the early and
even middle stages of the game, but can be
effective with a large enough pool of mana to
reliably cast the cards that might be exiled.
If only one card gets cast it is a poor
investment as a two for one with an added three
mana cost. In Booster it can be a matter
of preference, as it can be a benefit, though
actual removal or larger creatures would be a
better pick. In Sealed it depends on the
pool and can be filler when stretching Red's
ratio in a build, though when left in the
sidedeck it is unlikely to be missed.
Aggressive red decks are always running out of
cards. There spells are quick and cheap. Act on
Impulse is the latest way to try and do this.
For three mana, you get to look at three more
cards to potentially play this turn. While that
potential is real to play three more cards, this
is going to be difficult to use effectively. For
one, as the card says, you can play them THIS
TURN. If you don't, they are exiled forever and
you can't use them at all. After spending three
mana for Act on Impulse, do you have enough mana
left to play other spells? Later in the game you
might, but even if you do, you have to tap out
right then to play them, possibly making for
some suboptimal plays.
In short, I'd have to be pretty desperate to
play Act on Impulse. I might play it in limited
if I managed to get a very cheap deck, but I
don't see it being played elsewhere. There are
just too many better ways to get more cards.