Mardu Charm is pretty boss - it fights aggro, kills courser, stormbreath, thunderbreak, whisperwood, etc. AND is an INSTANT speed Duress which is really nice in the Control matchups - they tap out for dig end step, after they resolve it you Mardu Charm them - its pretty disgusting.

What is up I have been playing mardu for a while and I am thinking of moving in this direction with cards like Thunderbreak Regent and Stormbreath Dragon over cards like Butcher of the Horde. Also I recommend Draconic Roar over Lightning Strike looks solid +1

I haven't tried Mardu Charm, but I am not sure if it provides a significant enough upgrade over the other cards in the deck, especially in the three-drop slot. I agree that Mardu Charm is fantastic (though it doesn't quite kill Stormbreath, prot white and all), but I feel that it works a little better in a faster deck that is lower to the ground where you can really maximize on all three abilities.

yeah storms pro white i just mind blanked on that for a minute, but point being it kills a ton of stuff in standard at the 4 health range. only a few cards dont die to it, like Rhino, Tasigur, Sidisi undead vizier, etc.