If Carrara had the ability to import video and do motion tracking like Blender, I’d probably give up Poser. I know there is a plug in to do that now, but it kinda sucks.
I use Syntheyes 2011 with Carrara 8.5 Beta, Syntheyes has a syncar export option. Using PNG sequences works much better than video files. BUT your right… Direct tracking in Carrara would be awsome;)