leader the answer is "yes".
According to Epsilon and the Direct Marketing Association's
Email Experience Council report of April, 2012, triggered messages
had 96% higher open rates and 125% higher click rates than
"business as usual" messages.
See the report here:
Epsilon | Q4 2011 North America Email Trend Results: Open Rates Increase Over Previous Quarter and Year
I know this question has been raised before about broadcast vs. autoresponders.