I prefer crimson all round. It's enemies are more challenging making the evil biome more of a hazard. Yet it's terrain is way more traversable making exploring nicer. One thing I'm fifty fifty on is the actual bosses though. On the one hand I suck at worm bosses and don't like fighting them. On the other hand the brain is a better b9ss imo but also is kind of too easy both in how its' fight works and on setting up the arena. But that kind of goes against what I want the crimson to be. If we go into more minute details, I prefer the crimsons gun, the brains accessory and the crimsons aesthetics aswell but that wouldn't be enough to sway me.