He is very good, and very rounded offering a wider variety of abilities that work well in any deck and as a result I find I play him in almost every green deck I build and 100% of the heavy/mono green decks
Rise of the Floodborn brought several powerhouse cards into the Ink type including Cinderella Stouthearted, Best Tragic Hero, and the deceptively effective Let the Storm Rage On
When he transforms into Ifrit, all Ifrit's abilities are about fighting other creatures, because in the game, you're always fighting those big epic boss battles as Ifrit
Dryad Militant basically eats any spell that goes to the graveyard from anywhere, which helps slow down Faithless Looting, Snapcaster Mage, and even Delve decks by giving our opponent fewer cards in the graveyard to delve away
Nobody is going to want to drop an Ulamog, the Ceaseless Hunger down and leave it sitting out for your next turn
The payoff cards also work normally as long as youve completed a dungeon