They’re both equally as correct. You use whatever help you sleep best at night 
Since I’m lazy, I always use rc directly (unscoped)
rc.varName;
unless I want to set a default value, in which case I use
event.getValue(‘varName’,‘default’)
Thanks!
~Brad
ColdBox Platform Evangelist
Ortus Solutions, Corp
E-mail: brad@coldbox.org
ColdBox Platform: http://www.coldbox.org
Blog: http://www.codersrevolution.com