Carrara is a great landscape program , I use it for generating backgrunds and it 8imports obj files nicely, so pose in poser or daz studio and import to Carrara .

Lightwave is a modeller , renderer, animation etc package.  Its unfair to compare them directly.

For a hobbiest who does a little modelling I would get Carrara for scenery , and pick up the FREE Truespace at www.caligari.com