I tried Serendipity twice and both times I thought the frozen hot chocolate was just average.
It was most likely overhyped which caused these unattainable expectations in my head. With all the hype surrounding it I thought they might have used some crazy liquid nitrogen machine to give it some crazy textures and bring out different flavors in the chocolate.
No, it's just a very sweet milkshake which is dressed up with whip cream and chocolate shavings. It tastes good, very sweet and basically is what you expect after reading the ingredients and the preparation process.
I'd give it a 2.5 after all is said and done, and bump it to a 3 for location. Caesar's palace can be quite the adventure, I'm glad Serendipity is right int he front and easy to find.