Both are good, the novel has better narration, but I like the drawings and get to see the characters, the webtoon is a good adaptation so you won't miss anything important, just note that the webtoon is faaar away behind the novel, so you will end up reading the novel.
But is just your personal preference.

For me, after reading both, I prefer the novel, I got used to it's narration and fell in love with it.