Stormchaser,

I think you need to decide what you want another render engine for.  Funny you should be looking at Carrara, and Vue, as both have architecture the others don't

Carrara is a modeler.  You will be doing alot of work on the mesh's of you figures with it.  Wether you are or wether you are not handy with Poser's Magnets, a full fledged Modeler will help you make your characters even more beautiful!

Vue is a fantastic landscape/atmosphere genrerator. Carrara has some of this, but Vue is all about it...With vue you're making beautiful scenes yo put your figure into.

So you get to decide, do you want to work in your figures or all around them?

 

=  )