Keep in mind, there are no right or wrong answers. Simply picture yourself at both races and answer the question "which one are you more excited to be at?"
Ultimately the clock struck midnight for Steelhead, as it could not overcome the many rave reviews I've heard about Ironman Mt. Tremblant (Quebec, Canada). By all accounts it's an incredible venue with pristine water, a great course, and terrific support. It is my 2015 Ironman Challenge champion.