It's a bit win-more as you need to have a board presence to cast it, but a mere 4/1 is enough to give it a reasonable cost. But it's easy enough to land a 5-power guy on turn 3 in green with other mana accelerants, so this comes down on turn 4.
This is reasonable for six mana (and casting it for six is trivial) - stuff like Soul of the Harvest and Zendikars' Resurgence see reasonable play and this is arguably better than either unless you are forced to pay the full amount. And it's bonkers for a deck like Rhonas in Commander that can reliably slam it turn 4 or drop it for GG to immediately chain into bodies. Embercleave is probably the best of the cycle for Standard, but this is a close second and is by far the best for EDH.
Definitely find room in some of my decks. My Patron of the Orochi gets the best of it I think. Costing gg with the commander out, basically meaning it costs you nothing to cast as you can get the mana back straight away and the draw effect is perfect for creature heavy decks.