I say pick the medium that's going to work best for your situation and use it. Doesn't matter what it is if it works. What I really hate is duplication. Having to send one email to one group, then another email with a special attachment with the SAME INFORMATION to another. Also sending an email out with current update information, and then getting people who I just emailed call me on the phone: "I saw your email, is that estimate accurate?" YESSS! Fuck.