Pretty good! Though mine was lacking the white foam seen in the photo. Is the recipe missing egg white, or did I just not shake for long enough? I also forgot to add the nutmeg which might've played a part in it. Still, very tasty and light.
I finally decided to buy a bottle of falernum today and this was the first cocktail I tried making with it. Very pleasing margarita, though maybe not for my first experience with falernum since the tequila flavour kind of covered it up. Still, would definitely make this again.