Keeping this short and sweet. Go for the desserts, skip the meals/food here. There food isn't anything that has wow factor, but as others has said it's typical American fare but jacked up about $5 a plate.
This place is always super busy as well so either go at an "odd" time or when you're not starving.
Pros:
-The desserts! It's what their reputation was built on...
-The pinky pink décor, it makes you feel like you're in a sweet shop
-Our server was very nice and attentive
Cons:
-Pricey - you're on the strip...at the foot of Ceasar's Palace you pay for that locale
-The food wasn't worth the price; it was good and freshly prepared but so is Applebee's and IHOP. They just have prettier plating.
-Always busy, expect a min 20min wait
-Don't get the Frozen Hot Chocolate with alcohol, it's expensive and you will NOT get a buzz (if that's what you were expecting.)
Tips: Park Valet at Ceasar's and tell them you're going to Serendipity. The valet was totally full but when we pulled up and said that we just were going there, they gave us this special valet card and were only steps away versus parking in the garage and being .5 miles away.