If you use the Lacerte eSignature tool, the 8879's and the client copy are automatically attached when you send the request.  If using SmartVault, the 8879's and client copy would be saved to your computer first then attached during the send process.  In Lacerte you also have a dashboard that shows the progress of all eSignatures sent, I'm not sure if SmartVault has this. 

Either way, I have customers who use both and are happy with the process in each case.