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.
“At first, I spend about four hours a day writing. Toward the end of a book, I spend up to 16 hours a day on it, because all I want to do is make it good and get it done.”