"most of all, 100 % of our customers and partners did work with the same software we did: Office, Adobe photoshop/illustrator/indesign /quark xpress."
And what about the consumer, the person who you hoped to read the product? Were there supposed to have a copy of Quark Xpress to read it? If all you were doing was print it you wouldn't need to have gone near PDF.
If you wanted it to have been read online then if you wanted to ensure they saw what you saw you'd have little option; your reader with Word or Word viewer might not have had the same fonts, or even fonts with the same metrics. Your reader then sees a slightly dishevelled document and forms their view of whoever sent it accordingly: remember that what's communicated is what's received, not what's transmitted.