Action Mailer ... and two styles to choose from

It appears there are two ways to create mail with Action Mailer:

I use this way, I noticed exception_notification does as well:

def confirm(order)   subject "Some subject"   recipients   from @@from   body :order => order end

AWDwR P1.00 printing, November 22, 2006 uses this way:

def confirm(order)   @subject = "Pragmatic Store Order Confirmation"   @recipients =   @from = ''   @sent_on =   @body["order"] = order end

The later has been around as long as I can remember, while I _thought_ the former was the "newer" way. It seems much cleaner, but it would be nice to clear up the confusion on where this all stands. Which should be used going forward?