I agree on the lack of tutorials with Carrara.  There are several things I find a bit frustrating about Carrara.  The main issue is the shaders area.  There are lots of ways to create subtle shaders within Carrara, but they aren't always blatantly obvious.  Unlike Daz Studio which basically has presets for things like Metal and Skin, Carrara has none of this.  When I import a scene into Carrara, it seems to always turns specularity to 100%.  So, you get this tiny pinpoint specular highlight...even with Daz content! Not only is this frustrating, it's time consuming to fix it each and every time.  

Of course, once you get all of the shaders perfect, you can easily reload that saved file and work with it again and possibly apply the shaders to another figure later.  And that brings up another point. Carrara needs a way to allow easy storage and application of specific in-shader settings like Glossiness, Specularity, Bump maps, etc.  So that you can easily store sub-shader settings and apply them to only 'skin' objects, for example.  I believe you may be able to save them to files, but it really should be a palette of these user defined presets inside Carrara.

Carrara's renderer is quite capable of producing high quality images.  The main problem is in setting up the shaders to get it to do it.  Can it produce what Lightwave can?  Perhaps, but I have no experience with such a test.

As for another example of an issue, (and perhaps one of the plugins fixes this issue) the bigger you make a specular highlight, the more diffused it becomes (doesn't have a crisp edge).  I guess Daz felt that the bigger it gets, the less tight it should be.  I don't like this about Carrara's specularity settings.  There should be a setting to allow for tight specular highlights no matter how big or small the specular highlight is.  Certain materials require very tight, but larger, specular highlights.  If there is a way to fix this issue, I've yet to find it.  If it's not possible, then these are the kinds of issues that will prevent perfectly realistic scenes out of Carrara.

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Brian