This thing costs an effective eight mana to transform (less if you control other towns), and you still need to crew it once it becomes airborne, but thats a nice card advantage vehicle hiding on the back half of the land
Some stores also throw in extra prizes for players who go undefeated, though this isn't always the case
Three-chapter summons like this are only good for one attack or two block steps, so most of their value is tied into their abilities
Don't forget, Gush is a very real card, and the interaction with Foil is scary enough that some people feel Foil will be the final straw to remove Gush from the format permanently
Whenever Grunn attacks alone, double its power and toughness until end of turn
Also, it gives opponents an option on how to pay Phyrexian mana for their creatures to attack