Purchasing Communication Methods to the suppliers Email Pros and Cons and feed back

 My client is using FAX communication method as Purchasing Communication Methods to the suppliers .They are planning to use eMail going forward.Before taking this decision they would like to know the “pros and cons" and other customer feed backs on eMail communication method.Could you please give few artifacts,Customer feed backs,Use cases.We are on 11.5.10.2

Thank you so much for the inputs.

Supplier is concern about the mail format they are expecting the mail content should be same is Print PDF.Can you please throw some light !!!!