Carrara is capable of doing anything from exotic natural backgrounds to advanced model space ships and some great animations.  I also had Bryce, but honestly, I never needed it after I got Carrara 5 a few years back.  Carrara can import/open poser files as well as many other formats that other packages use.   I has an excellent shader room, and if you are used to dealing with Bryce's horrible interface, you will be in love with the simplicity of Carrara's.  It has separate rooms for assembly, modeling (Spline, Vertex, or Metaball), and rendering.  I would highly advise getting it over Bryce.  It is just so much more powerful and flexible.