Despite that being the back of the card, the Vehicle sides are almost always cheaper, and the intended play pattern seems to be that you cast that half, fulfill some condition, and flip into the powerful Robot
The background, artwork, text boxes, and frames are all printed first, while the mana cost, set symbol, and text are done at the end of the process
But I have some personal thoughts, too
Its always a bit personal which one you like better
Phyrexian Vatmother Phyrexian Vatmother is an awesome infect creature to have on the board because it has 4 power
It slots nicely into decks that care about going wide or using citizens, especially alongside commanders like Samut, the Driving Force or Jinnie Fay, Jetmir's Second