One of the things we brought back from our trip to Edmonton a few weeks ago was a variety box of Halloween candy: Aero, Coffee Crisp, Smarties, and KitKats.
In Canada, KitKats are a Nestle product while in the US, they’re a Hershey product manufactured under license from Nestle. Size differences aside, they’re also a little bit different on the inside.
First thing that’s noticeable is that the layer (chocolate?) between the wafers is darker and more distinct in the Canadian KitKat. It’s hard to tell there’s anything between the wafer layers of the US KitKat, but it turns out the inter-wafer stuff just a different colour.
Taste-wise, the Candian KitKat seems a little crisper, and a bit more chocolatey than the US KitKat. If I was doing a taste test, I’d choose the Canadian KitKat.