Learning to use Carrara 5 has been my major effort lately. With Transposer it has been fairly easy to import characters and props. Experimenting and reading the manual and various tutorials and forum posts has allowed me to be able to get a few renders finished. Usually I have a specific goal to achieve with each render I've done in C5.
I have learned a little about the lights, shaders, presets, and render settings. I love that the light-sources can be made visible in the render. Many effects can be added to the lights. These are effects that require much setup and work in Poser and Imagine, the 2 3d apps I use.
It will take a while, but I feel confident that I can get a lot done with C5. It certainly renders much better and faster than Poser 6.