WriteItNow is an application that has many tools to assist in the structuring, creation, and organization of a novel-length work. It has a variety of downloadable extras like historical data, "prompts" to coach you in structuring Acts in a 3-Act work, provide inspiration, etc.
The word-processing tools are minimal, but all the essential items are present; export options are many; and character creation features are comprehensive.
The UI is straight-forward, allowing the user to find and access a tool easily. That said, the help files are detailed and the manual is superb, not just detailing how to find a feature, but giving insight into its use.
The software is under constant development and new features are added form time to time to increase its value to the dedicated writer. The publisher provides email support.
The download is free, but work cannot be saved without purchasing a licence.