NPrinting has changed a little bit in the past few weeks as it has been bought by Qlik.
Designer (or Client as it used to be called) is your basic version that enables you to create static reports (Excel, Word, PPT, HTML) from QlikView.
Server enables you to schedule these reports so that they run as a service.
On Demand allows you to build a QlikView interface where Users can choose to trigger reports to be produced.
The advantage of NPrinting is that it is a lot more stable than using Macros. Macros can sometimes fail for no vald reason when triggered by QLikView. NPrinting is designed for the job of producing reports and to distribute reports automatically to email, folders or Google Drive. Now that it has been bought by Qlik it will be supported and considered in all future Qlik enhancements.
From an IT perspective, the risk of using NPrinting is lower than Macros.
Additionally to Neil's comments, NPrinting allows you to easily distribute and schedule distribution of static reports throughout the enterprise to the people that need to have them and the specific data they need to see and at the time they need to have them.
NPrinting Resource Library
NPrinting Knowledge Base on the Original Vizubi Site Customer Feedback for Vizubi