NLC is basically a middleground between hiring a freelancer for every new project and hiring a full-time inhouse designer. We tried both routes before and both did not work well for us.
The huge advantage with NLC is that they have many different designers with different skillsets and they usually assign the right one depending on the type of task you submit (or you can select a specific designer).
Turnaround time is fast, communication crystal clear. Super happy with the team so far!