Great cocktail. I was traveling and didn't have any creme de cacao on hand, so I used a bit of Licor 43 instead, and floated 3 coffee beans on it instead of chocolate (which I also didn't have). It was excellent.
I'm sure it's sacrilege, but I occasionally switch out the Lillet Blanc for Italicus and then add some grapefruit bitters and a twist. It has more power to battle the bitterness of the Suze, and the result is exceptional and balanced.