I was told by one of your Service Advisors that my 2014 Prius should be run in the General mode around town and the Eco mode on the freeways. Everything that I can find on the subject on thei internet says the opposite. Which is true?

The owner's manual is the authority and go to resource.

Robert Sometimes the info on the internet and through different forums can be confusing. In the owners manual PDF on Toyota’s website found on page 11 gives more information. The ECO mode helps achieve lower fuel consumption during trips that involve frequent accelerating and braking.

I don't drive a Prius, so I honestly can't tell you. I would go back to a Toyota dealer and have a manager clarify what you found on the internet. The owner manual is another way to clarify to.