This card really suffered from the mana burn rule change, but it's still pretty good. It locks down other decks and basically works kind of like a poor man's Dosan the Falling Leaf, albeit it doesn't stop nonland mana sources like Manalith. Still, it works pretty effectively against counter decks. While it can hurt you, there are a lot of decks (burn decks for example) that can easily thrive playing playing only on their own turn (usually because they don't have a hand to play afterwards). One of the best decks that I've ever seen with this ran Pyromancer's Swath because the player could never keep a full hand anyway and never needed to keep land untapped. One that was really good before mana burn went away ran Chimeric Idol to avoid the aforementioned mana burn (also, it avoided the damage from Manabarbs, which is this card's best friend). All in all, a really good card that needs to be built around. It's not something that you can just throw into a deck willy-nilly.
Pros: Locks down Instant or EOT-based decks
Cons: Potential to hurt you