It's really good in decks that want to go wide.
Certainly not too powerful, but it is good in the right deck. I'm personally not someone who thinks any card is an auto include, so I wouldn't go that far myself, but I can see the argument.
A friend of mine has one in a Selesnya token deck he runs and has used it to great effect both offensively and defensively. I think that's probably the best thing about it. It's very flexible. It can close out a game or prevent the caster from losing everything (which in turn will probably close out the game as a result anyway).