This plugin is built on the foundation laid by VdF. I wrote it for my own use to address what I perceive as limitations in the VdF plugin.
It should be noted that the full potential of this source plugin can only be obtained if the plugin is used alone. Indeed, used with other plugin(s), calibre looks for a match on title, authors and IDs... Calibre then merges all matching results to give a maximum of relevant information.
If, as I prefer, you want information from babelio and babelio only, you should select babelio alone and keep more than one entry per source (per plugin). The usefulness is apparent for searches such as "henri verne Les dents du tigre 2" which returns "Les dents du tigre (2/2)" first followed by "Les dents du tigre (1/2)", or a search on "Paulo Coelho Guerrier de Lumière" which returns four different books.
Once the babelio information has been uploaded, I augment it by uploading from all plugins only the labels and cover images (for example). I could also load the notes in order to weight the ones given by babelio, etc...
So I wrote a configuration for this plugin.
I kept the function to avoid searching for a cover. In fact, because the cover image is sometimes on amazon, and because amazon isn't really responsive to non-human access, this feature turns out in some cases to be really useful. You go from waiting ten seconds or so to a handful of seconds. It's very appreciable when dealing with a series of titles.
I have implemented several levels of verbosity, by default level 3 will give the progress in the log. In particular, it could be that the plugin does not provide the editor, in which case a quick look at the log will show whether it is a plugin bug or a lack of babelio...
Finally, an important use of the template for me is to create a catalogue. In this catalogue, I like to be able to follow a link to the babelio site. This allows me to get more information about the author, his bibliography, the readers' opinions... So I create a reference that finds its place in the comments, and I separate it from the summary coming from the site by a title.
The best way to report a problem is to push the verbosity to the maximum (15), reproduce the problem and copy the log. A short description of the bug with the log will greatly help to understand and fix both the plugin and its documentation. Indeed, reporting that the title is not decoded correctly when multiple plugins are selected is probably the normal operation of calibre, so it should be documented.