In the owners manual on page 141 it says that with the ecoboost engines, premium fuel provides improved performance. Further it says premium is recommended for server duty like trailer towing. Also, in the Escape review(posted in one of this websites forums) it says: "It’s important to note that if you decide to feed your Ecoboost engine regular unleaded, you’ll experience about a 10HP power drop vs Premium". With that said, premium fuel improved performance = improved gas mileage (with all else being equal). So is the extra $$ worth the improved mileage under normal non severe conditions, I don't know?? But if I buy a boat and tow it over the cascade mountains on a hot summer day, it will be with premium in it.