I’ve been using it for a while.
Octane seems to have trouble with Carrara’s smoothing (or lack of it), though, so I export the object from Carrara, import it into DS, then export it again as an obj, and then import the mesh into Octane. Opacity maps get lost for some reason and have to be added manually.
I like the results. Also, word on the Otoy forums is that someone will develop a Carrara plugin for Octane as soon as they’re finished with the DS one.
http://www.renderosity.com/mod/gallery/media/folder_235/file_2343826.jpg is a render I did a long while ago on my ‘rosity gallery.