I've tried it now, and actually I'm wondering if it is real NPR or just a postwork filter?  anybody know?

Love esther

As far as I can tell it is a mix. You need to activate it before starting a render and then Vue collects additional info with the render (similar to G-buffer/layers). This information is then used in post processing to apply the effects. So without activating the NPR render you cannot use it, but it is not applying the effects directly during rendering. This has the advantage that you are not locked into one style, but can also be limiting especially when one tries to use it with animation. What I found is that it is best to replace all materials with simple ones for NPR. That gives very fast render times and most detail doesn't matter if you use the NPR styles. So, it is more than "just" postwork, but less than a NPR that works at the shader level. Which one is better will depend on what you want to accomplish.
Ciao

TD