I like this set of lands. Sure, they're not the greatest cards to be printed, but they have their uses. With a Crucible of Worlds out, these lands can effectively double their output every 2 turns, which can really give you a leg up. The problem with this combo however (and these cards in general) is that these cards come into play tapped, which mean without something like an Amulet of Vigor, you'll only be using these lands every second turn. Other than that, these cards aren't bad.
Pros: Can be sacked for double mana
Cons: Enter tapped