humm
Honestly I used to do all of my modeling in Carrara, but lately I've started using Silo (which is another reasonably priced MODELING program) and using Carrara for tweaks and fine tuning. This because unlike most other modeling programs (including C4D)  Carrara works very well in Poser;s native scale. When modeling in other programs I;ve found that you almost have to work in a larger scale (mostly 10x for me) and scale the items down to fit in poser.

Silo is a bit easier on the computer resources and has a UV system capable of "pelt" map style work, but then again Carrara now has this as well and reports say some of the memory leaks may have been plugged so I may go back to it as a primary. I like that Carrara has a rendering engine that is fast and gives excellent results. Silo doesn;t have any rendering so you have to export and use a good render (like Carrara) to see what final models will really look like.

As far as resources... heck, I buy and read books for ALL of the modeling programs. Most of the techniques are the same just the details of the tools used are somewhat different. Will a little work the resource that are out there can all be read for use in Carrara.

Personally if Carrara suits your needs why move to a "Pro" program, unless you envision working for a major graphics house and then you should concentrate on one they are using, for gaming 90% Max, for film and viceo seems to be XSI, Maya, etc. I don;t think more than a fraction of the major houses are using C4D, so why spend the money?

Just my opinion,
mike