In a set review, except for something crazy like Phyrexian mana, its hard to tell
Cards like Underground Sea are nonbasic lands with two basic land types, in this case, being both an Island and a Swamp
Wizards of the Coast designs mythic rares to carry more impact per card than any other rarity
For example, if you have a Nissa, Steward of Elements in play and you cast a second one, you have to pick one that you keep in play and the other will go to the graveyard
The same four things a professional grader judges
*Now before we get into numbers 3 and 2, these two cards can be very interchangeable when it comes to where they fall in the standings