Looks like they have achieved what they set out to do. Make a very decent, well engineered hot hatch.
From the press I was aware that Hyundai and Kia were trying to establish something in their branding beyond well built, well equipped cars. It's such a competitive market they are trying to define themselves and stand out from the masses.
You can tell by who they head hunted to achieve this that they are very serious. Hopefully some of the engineering skills and capabilities that come from the N sub brand and it's component suppliers will find their way into the mainstream cars.
It's not long ago that the idea of a Hyundai costing around £40k was unthinkable. N will add desirability to the brand. Next step is to increase the perceived longevity, making the cars feel as new for longer.
It'll be a hard hit on depreciation with the N though, until it becomes established as a brand.