[Suzerain of Sheol]

For the most part, 1st-person will only work if the story follows one character from beginning to end and never branches away. This obviously limits the scope of the tale to whatever the narrator directly experiences. It also forces the narrator's bias onto how the reader sees the other characters.

In contrast, 3rd-person can follow multiple points of view and tell more elaborate, intricate stories that show different facets of the characters' personalities.

They both have their advantages, but I think 3rd-person is more widely applicable. You have to want to tell a very specific kind of story for 1st-person to work.

I have seen book that have multiple 1st-person points of view, but those tend to be rarer and I don't have enough experience with them to decide if they work as well as 3rd-person for layering the story.