Not OP, but I was an early contributor to Draft. Draft JS lacks a few features, notably nested block support (tables) and a schema definition and sanitization.

Not OP, but I was an early contributor to Draft. Draft JS lacks a few features, notably nested block support (tables) and a schema definition and sanitization. Slate is more focused on providing a nice plugin experience. On the plus side Draft’s core is battle tested and has just picked up Android support, and has the excellent Draft JS Plugins resource.