As a quick suggestion, if you're using Poser 5 or 6 to set up figures to be rendered in Carrara, pretend that you're still using ProPack or Poser 4 (with the exception of bump. Don't use those old .bum files ... use .jpg bump maps, if any.) In other words, don't include any procedural shaders in your Materials Room setup ... they won't translate properly in Carrara. Don't use Shader Spider partial shaders or Occlusion Master settings. You can get better AO effects in Carrara, anyway.

It's true that you'll need to tweak some settings after importing into Carrara, but the same is true when exporting from Poser to Vue, or I suspect, any other app. Just accepting the default values post-import won't yield optimal results. Once you've taken the time to tweak details a bit, you'll probably come to agree that Carrara is by far the superior rendering app, even when compared to the fanciest Firefly settings in Poser 6. I had the same "too shiny" and "plastic doll" issues at first, but that's only because I wasn't changing anything after importing into Carrara.

Most satisfactory for this Carrara newbie is the app's much faster rendering times. I was pretty tired of spending several minutes watching Poser calculate shadow maps slowly, then causing my HDD to make bizarre grinding noises during render that no other app causes. With Carrara, complex scenes that Poser 6 can't really handle on my computer render relatively quickly, and without the evident strain on resources and hardware.

Sorry Poser. I loved you for years, but you've got issues, issues.    :-)