On the US keyboard, the enter key is only one key height and longer, and the left shift key is longer. This moves a couple of keys around (`\). The most notable (especially from a programming point of view) is that the " and @ keys are switched. I use strings way more than I do anything else, so the US way is preferable here as its on the home row. The pound sign disappears, but I don't think I've ever actually needed it, while I need $ all the time.

Perhaps minor, but as I say, noticeable when I switch keyboards that its an annoyance.

Edit: added some text