materials migrated to cycles have low contrast

Hi all,
trying to get my head around blender and have been toying around with some models I found and imported from XNALara meshes. Unfortunately the materials were imported for the Blender Render, while I feel like starting with Cycles right away (seems pretty powerful.)
So, I went and converted all materials to cycles with nodes and that worked rather well.

Comparing the rendered images, however, the cycles rendered one looks smoother, but also a bit bland, i. e. low contrasty.
Is that because I upped the samples to 500, because I need to tweak the lighting, now, or is there a general issue with the conversion plugin from BI to cycles?