I am just going to let the facts do my speaking;
"The U.S. Centers for Disease Control and Prevention (CDC) reports that more than 37,000 annual U.S. deaths, including more than 1,400 in Colorado, are attributed to alcohol use alone (i.e. this figure does not include accidental deaths). On the other hand, the CDC does not even have a category for deaths caused by the use of marijuana."
Sited from http://archive.saferchoice.org/content/view/24/53/
"Whether it’s used as an excuse for or directly causes aggression, alcohol more than any other substance promotes violent behavior. In case you’re unaware, marijuana tends to chill people out."
Sited from http://www.hightimes.com/read/10-reasons-marijuana-better-you-alcohol
"In 2002, a special Canadian Senate Committee completed an exhaustive review of marijuana and health, concluding, "Scientific evidence overwhelmingly indicates that cannabis is substantially less harmful than alcohol and should be treated not as a criminal issue but as a social and public health issue."
Sited from http://www.huffingtonpost.com/paul-armentano/alcohol-or-cannabis_b_3799972.html
need I find more