What are some alternatives?
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
iA Writer - Minimal Design, Maximum Focus
Remember The Milk - Remember The Milk is a task and time management application for mobile devices.
Haroopad - Haroopad is a markdown enabled document processor for creating web-friendly documents.
WorkFlowy - WorkFlowy is an organizational tool that makes life easier. It's a surprisingly powerful way to take notes, make lists, collaborate, brainstorm, plan and generally organize your brain.
StackEdit - Full-featured, open-source Markdown editor based on PageDown, the Markdown library used by Stack Overflow and the other Stack Exchange sites.