I wouldn't compare Vue and Carrara at all ...

In my opinion they don't really compare - each program can do fine things in 3D-graphics - and each got it's specialties. I own Vue 6 Infinite and Carrara 5 both.

The strength of Vue is definitely mainly landscaping and really special atmospheres - to achieve a photoreal look in landscapes. I don't believe you are able to get that close with Carrara. Carrara got it's strength in a strong 3D construction part with lots of possibilites like single 3D-modelers and a powerful renderer for certain scenes.
The texture and material possibilities in both programs are very detailed with lots of options.

They maybe left out the boolean and primitive modelling, because if you know Carrara, it got a much more powerful modeler part.
In Vue you can do some good modelling, yes, but not to the degree of a real modelling program like Hexagon or others of that kind, or Carrara's modeler offers ... the modelling options aren't really a strength of Vue in my opinion - but that's not what's it's made for.

I like Vue, for what it can do and not for what it can't do - for the other needs i have other programs.
And the easiest way, to be able to see, what you can do and achieve with Vue or Carrara, is to take a look at all the images done by users of each program. There you should be able to tell, which one suits your needs the best.

So basically the producers or sellers of those programs shouldn't show a comparison list with other programs, they should stick by only displaying a list, what it can do.