I tapped my Swamp to cast Sol Ring, leaving up Island, with a Power Sink and Terror in hand
Emerald/Ruby is a control-style deck that has some strong advantages in multiplayer and does a great job stalling the Steel/Sapphire starter deck in particular
Four booster packs for $230 (this price was leaked by Amazon and has since been deleted, but is likely accurate) is the hardest sale Wizards has tried to make, but it might not be as bad as players immediately assume
I can see it being a useful sideboard card, but very infrequently
We have a frequently asked questions page you can find here
They'd be gaining massive card advantage, but what use is it your opponent is down four lands, he's out of cards, and you are dead