Great skin depends first and foremost on great maps. I'm not talking about your run of the mill photo maps, I mean different maps for diffuse, bump, specular, SSS, and even blemishes. You rarely get proper bump maps with poser textures, let alone proper specular and SSS maps. Carrara has one immediate weakness over most other apps that use Subsurface Scattering, in that the new SSS feature is not able to be defined by a control map. It doesn't kill the feature's usefulness, just doesn't give you much control over where the SSS is, and how much of it is there. I've seen this is very much a useful feature mentioned a lot on CGTalk when they talk about Mental Ray's SSS Skin shader.