Dave H. Staff replied 4 years ago

It doesn’t really matter – taxonomies can be hierarchical, so if you don’t need hierarchical then use attributes. There are a few extra display options for attributes rather than taxonomies.

Kostas M. replied 4 years ago

Thanks for you quick reply … also we are testing several technologies in order to cover a site with 500k books and also we are going to purchase your power pack to test it against this setup.
So, we have a lot of contributors(#18) for each book (Author, Translator, Performed by, Illustrator, Editor, Photographer, Composer, Body etc) what is the best method for your plugins, to have separate custom taxonomies or attributes. Just to mention that for each contributor there are thousands entries as you can understand.