The lighting and rendering setup in your Carrara scene is very basic. You aren't taking advantage of Carrara's capabilities at all. Have you learned to use GI, indirect lighting, HDRI, soft shadows, less ambient light, light color, or 3 point backlighting? Carrara has a much better render engine than Poser, but you need to learn how to take advantage of it. It wouldn't be much work for someone who knows Carrara to make your model look better than in the Poser render.