I wouldn't say one is easier or more difficult, but when you're inside a costume and a mask, you have to endure heat - and, often, difficulty seeing. The vision is not very good in a mask. And you have to cope with that, as well as trying to think about this character.
Let's face facts, this is visual medium, there's a very high premium put on people who are good-looking. But the minute you rely on that you get yourself in trouble. You certainly don't make a career out of that anymore as an actor.