I haven't had a lot of luck with it. With large (tens of MB) PDFs it silently fails to add the source. With smaller PDFs I don't need a machine to summarize them. For dense, factual materials it just invents things that are not true. As an example of the latter, I added a source from the inventory of housing construction opportunity sites in the city of Berkeley, asked some basic factual questions, and it just blends numbers from the source together into a soup of lies.