I made these for my birthday and everyone loved them. I used mint leaves instead of basil, and Patron as my silver tequila.
Oh my goodness this was terrible. I made a batch for a dinner party and when the first guest handed her glass back to me still full, I dumped it and got out the back-up bottled margarita mix. She said, "This doesn't taste like a margarita. It just takes like weird watermelon juice." Gah! The watermelon ice cubes were very cute though, used them in other drinks.