In terms of ordinary use cases, really nothing. It's like MS Word. The best possible option in a perfect world? No, but it gets the job done. Common complaints: subscriptions are quite expensive, customer service can be hit-or-miss at best, and they have a habit of changing features people like in favor features people don't like. They're also pretty grabby with donations. For an average donation of $3, they take almost half. For a $1 donation, they take all of it then charge you a few cents more. So many zines would find a viable competitor to be a breath of fresh air.