One of the interesting things I seem to have noticed if my email adverts and some quick investigation seems to reveal is that there are some stunning human characters for little cost for things like DAZstudio and Poser, but it is slim pickings for the mighty apps like Maya and Max.
If you look at V4 and Aiko and the vast numbers of variants you can get via DAZ or 3rd party sites like Renderosity with their myriad of vendors. Even if I look in ContentParadise for 3ds Max characters, they are actually all based off the poser and DAZ ones.
Turbo Squid have things like Masha and Alicia, but in comparison - well there isnt any.
I find it rather amazing that the art of creating wonderful characters is really rather specialised, yet for Max/Maya/Etc there arent a wealth of content providers that seem to bring the same quality that the poorer cousins like DAZstudio and Poser bring.
There are plenty of folk out there who go through the headache of moving things over from these apps to the likes of Max, Maya and more. What I think the state of play should be is that the amazing work that is done for the simpler apps was easily used in the gruntier modellers, that way people can leverage each others talent rather than starting from scratch. Perhaps Carrara 6 is worth a closer look for this reason...
Just check what V4 and Aiko can do with a few morph packs in the simpler 3D apps - stunning.
[Poser and DAZstudio art and store imagery from Renderosity's Gallery]