Thanks for the update!
I tested it with "Iain M. Banks - Pensa a fleba".
This title is listed in both anobii and bol: the comments are retrieved correctly from both sites.
By the way, it would be nice, in a future update, to skip the downloading of the default cover from bol.
At the moment I just run a script that removes the cover.jpg files with a size of 15941 bytes: I guess there should be a clever way to do that ;-)