I recommend reading lots of both genres to get a feel for the kinds of stories they deal with and how they are written. You'll see varied advice "out there" such as "early readers are dead". Therefore it's best to read widely from many sources - publishers, editors, bloggers, reviewers, authors and illustrators, and make up your own mind. I had a picture book manuscript deal cancelled by a small publisher about 15 years ago because the publisher was advised by one contracted editor that "e-books were the future and picture books were dead".