While Carrara isn't used on all of my projects, I do use it more than any of the other 3D apps. 

Carrara is in a funky marketing space. It's inexpensive enough that hobby folks can afford it. That means that there are a bunch of people using it with no 3D training or pro aspirations so you'll see more mediocre imagery than with the "pro" apps because hobbiest simply aren't usually invested enough to actually learn the software. You'll also hear loud complaining from the hobby market about Carrara because, somehow, the software should require no learning yet magically produce Pixar level imagery. All 3D apps require focused learning to use them well.

Professionally, I'm simply pragmatic and big on speed in the studio. C4d and Maya etc. are great applications but they are squarely aimed at the cinematic market. As a result, their procedures, maintenance costs and plug-in costs are a bit of overkill for most of my projects. 

If you're going to be doing mostly TV and integrate with video and post shops, Maya, LW et all are the standard to be sure and you would be well served to ante up the bucks and tackle the learning curve. However, they each have some inherited pathologies that make them less useful for other needs that are common to advertising and MarCom.

I do use a host of 3D packages but tend to use Carrara as a Swiss Army Knife - it does a lot of things very well, for all medias, print, web, and video.

I'm cautiously optimistic that Carrara will be getting some of the features that the cinematic applications have. Pro pipelines need things like  multipass rendering and that has been voiced to the developers rather loudly. There are some plug-ins for Carrara that are every bit as sophisticated as Maya plugs, but at about 1/10 to 1/20 the cost. As an owner/operator of the studio, that's appealing.

To be sure, Maya and other similar apps have outstanding pedigree and capability. But a quick spin through the galleries here will reenforce that it's the operator more than the software that makes the difference. While Carrara started out as a hobbiest and quasi pro package, it's definitely a pro level software now. I can say for certain that Carrara is now used in many of the video studios I freelance for simply because you can do many "routine" 3D tasks faster. 

I can also tell you that you've seen Carrara animations on television but didn't realize it. ;-)   I can't really say how I know this, but broadcasts like the most recent Superbowl and the Emmys had some Carrara content transitioning for commercial breaks. The pros just learn it and use it - like everything else in their studios.

I love working with modo 301 and Vue 6i too but Carrara is actually more competent in many areas - especially if you need to work with human and animal content plus create original content, all at the same time.

All that said, I have yet to find the perfect 3D application. They all have stuff that frustrates and delights me, all at the same time. To adequately serve my client base, I have to maintain and be fluent in 7 3D packages. I've got the dead brain cells to prove it. :D   You're optimistic in thinking just one 3D application will make everybody happy!

However, fluency in the application, whatever it is,  trumps everything else.

Mark