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.
“So I was surprised at the notion that I might have brought anthrax to my home, and would have been even amused if it was not for the fact that this matter is so grave and serious.”