"Not much point for me to use Poser if I'm just going to load its content into Carrara and set up scenes there.  I'll stick with Poser."

You're right on the first part and it's your decision on the second part.  Carrara is a far more robust and powerful app than Poser, that said you will have to make some minor adjustments on your textures from Poser as Carrara reads them differently (mostly it makes poser skin too 'shiny' but by lowering hightlight and shininess you can correct that).

However there is no reason I can think of to want to load Carrara stuff into Poser, so if you're happy with Poser and intend it to be your rendering app, then there's no reason for Carrara at all.

I was very dissatisfied with how slow Poser was to render, so I picked up Carrara 7 (and have now upgraded to Carrara 8).  Poser does one thing better than Carrara at the moment, which is dynamic cloth (and the only reason I haven't deleted Poser from my computer altogether).  Carrara dynamic hair is phenomenal and blows away anything I've seen from any other app, also Carrara includes modeling capabilities, a much faster renderer, landscape-building features, (plants, ocean, buildings etc) and very extensive and precise lighting.  Posing in Carrara is (for me) far easier than any other app I've used (others may feel free to disagree) and also be wary of losing some morphs if you build in Carrara (the best way to preserve all morphs to the exact specs of Poser is to build your character first in Poser, then save it making sure that 'use limits' is checked.  Then import into Carrara and the morphs will all behave correctly; then retexture the skin in Carrara and save for future use).

Again Poser does do dynamic cloth better than Carrara (though with the new bullet physics softbody, Carrara is being worked on and getting closer).  For everything else, I use Carrara.

Not trying to bash Poser, even though I'm not a huge fan of Poser I still use it on occasion, just wanted to clarify about what Carrara can do.