Crimson, by miles. Granted, the enemies are a little tougher in the early game, but when you don't have to worry about a single light tap knocking you off your rope or thin ledge to splatter on the bottom of the chasm below, it balances out. Like most alternatives introduced after the originals, Crimson tools are generally slightly superior to their Corruption counterparts. In particular, Crimson armour grants the longevity that early game characters so desperately need while also benefiting all classes; Shadow armour mainly benefits swordfighters (melee speed doesn't help yoyos that much), and melee is definitely outperformed by the likes of ranger and mage loadouts pre-hardmode.
The Corruption also has the Worm Scarf in Expert Mode, which is definitely a point in its favour over the Brain of Confusion - but the likes of class-specific accessories and the various emblems will push it out come hardmode. The percent-based damage reduction certainly is useful throughout the entirety of Expert Mode, but it's a comfort I learned to live without.
And speaking of hardmode, the Crimson more or less instantly outshines the Corruption when you get there. Ichor darts, bullets, arrows, flasks, Golden Shower... ichor in general puts cursed flames to shame. Fetid Baghnakhs are a fun toy, and Vampire Knives are self-explanatory; all classes stand to gain something from Crimson, but melee has it especially good. It also provides components for the Heartreach and Rage potions that Corruption can't provide, and I personally love crit builds. All in all, Crimson all the way (except in the soundtrack department).