Carrara is capable of producing some fantastic images...but so is Poser.  They both have advantages and disadvantages.

Personally although I think the render engine in Carrara is fantastic, I hate the interface so Poser / Vue tend to be my main rendering tools.

I'd say that before you go paying for Carrara 6, why not try the download demo of Carrara 5 Pro?  Although it's not exactly the same as v6 it would give you an idea of what you're getting before you shell out your cash for it.

http://www.daz3d.com/i.x/support/downloads/-/?product=car_down

Apparently the full version is also available on issue 100 of 3D World.

i7 5960X, 32GB RAM, GTX 1080Ti, GTX 980 Ti, Windows 10 Professional.  Running Daz Studio 4.11, Poser 11, Vue Inf 7, Photoshop CS4