I got an alert saying you tagged me here... WatCorruption, and it's not because that I'm the Corruption Overlord.
Th corruption is pretty much approachable, it's loot is pretty much rewarding, and above all, a good biome for new players. I'd have to admit, the Crimson is powerful, challenging and unique, but still, it's not a good biome for new players.
So, yeah, Corruption all the way. Any thoughts @Qui Devorat?