Should I Be Ashamed For Buying An Engagement Ring From Tiffany & Co.?

My best friend says at Tiffany I am just paying for the name and that I can get a bigger diamond for the money I’m paying at another jeweler.
I think Tiffany represents elegance, class & timeless quality. I want my future wife to have the best. Nothing against Zales, Jarred, Kay or the other places.