On a second thought, the iPhone DOES have carrier branding
Most people hate crappy carrier brandings on their phones, one such example is the Verison Galaxy Note II-look at the ridiculous Verison logo on the home screen. My first phone to recomend to folks who hates carrier branding printed on the front,was the iPhone. Next up was the Moto X.
However, I rethought it and decided that the iPhone indeed does have carrier branding. It was built into the whole iOS. Yes, it was the status bar on top. On every single version of iOS (including iOS 7), there is your carrier in the status bar on the left.
Or actually it wasn't carrier branding, but more like carrier name.