The text is peppered with footnotes which, although almost by defintiion are not vital to the story, do neverthelesss add interest. IDK how audiobooks deal with them, but they may be easier with an eBook.

The footnotes are read in a different voice. Didn't hinder my experience at all. There were quite a lot of foreign words, due to explanations about etymologies and what not, some seem shaky, because it's highly unlikely that two voice actors would be fluent in so many languages, but neither am I, so I couldn't tell 100% and this wasn't an issue either. It's pretty long though, so maybe pick whichever format gets you through a lot of text better.