Same size, same 2 colors, 1 color per side. The Bureau of Engraving just changed the design to combat counterfeiting, including adding watermarks, but they missed a major opportunity to do it more thoroughly. Public acceptance may have a lot to do with that - witness the resounding apathy the latest $1 coins have been met with.
Vending machines and cash registers in the US are all made to accommodate same-size bills, so that change may not have been practical.
This is a bit late, but it did seem apropos given the multiple references in this thread to “Braille” dots on the currency of various countries (and, of course, to the OP).
The embossed identification marks on the Irish notes are not Braille; there’s a triangle on the fifty, a diamond over a horizontal line on the twenty and a diamond on the ten. I don’t know what’s on the five because I haven’t got any fives. On notes that aren’t brand new, it’s hard to distinguish them by touch (or maybe it takes practice).
Geez, that link died quickly. Maybe this one will still work.
Regardless, it was a news item from the Canadian mint asserting that with the introduction of the new Canadian $10 bill this week, Canada becomes the first country to use Braille on its bank notes.