Job Select is basically a reskinning of Living Weapon, For Mirrodin!, etc: you cast an equipment and it comes in with a token creature pre-equipped
Five rare creatures, each with powerful effects that trigger when they enter and leave the battlefield
Its ETB pumps your entire team with +X/+X and trample, where X is the number of creatures you control
So far, Wizards seems to have put a lot of effort into calculating the value of Secret Lair drops
Here's a list along with approximate preorder pricing: Call the Spirit Dragons ($20) Dracogenesis ($20) Stormscale Scion ($20) Teval, Arbiter of Virtue ($10) Shiko, Paragon of the Way ($10) Betor, Kin to All ($10) Neriv, Heart of the Storm ($8) Urnei, the Song Unending ($8) Tarkir: Dragonstorm is filled with many powerful Dragons and Dragon cards worth more than the price of a Play Booster (at least during prerelease)