V4's internal magnets seem to work (at least. magnetize clothing works) in C6Pro so I assume the same would be true for C7Pro. External magnets do not seem to work in C6, don't know about C7.

For the price of a magazine you get SSS, caustics, particles, plants, terrains, the ability to make any object into a light, etc. etc. etc. OTOH, unless you really crave those features, I'm not sure it's worth the investment, especially if you're happy with Poser. The price is cheap enough, and I doubt you'll find anything closer to Cinema 4D or Max for that money except maybe free Blender. There is an investment in time though. Carrara's learning curve is pretty easy for just importing and using Poser stuff, but at a minimum, you'll probably have to learn a new material interface for anything beyond basic materials. Needless to say, if you want to use all the other neat goodies, you'll have to learn them as well. The basics of working with Poser shouldn't be a problem.

Some people use Carrara, C4D, Vue, etc. primarily as consumers of Poser content and may not even use Poser at all. Some use Poser for basic scene setup and then go the the other applications to take advantage of better render engines, modeling, landscapes etc. If you're comfortable with Poser, then the former may be a difficult adjustment. Unless you feel a compelling need for the latter then you may be better off investing the time in Poser. With the possible exception of Vue for outdoor scenes, I'm not sure you're going to find any application that will, out of the box, produce better renders than a reasonably experienced person can get with Poser and even then, you'll probably want SkinVue for the Poser figures.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken