I've been to the NY Serendipity but that was over a decade ago! So I couldn't remember exactly what the frozen hot chocolate tasted like anymore.
Overall, the quality here is a solid ok. I think if you were to order one thing, the Frozen Hot Chocolate is the way to go!!!
We also ordered a strawberry milkshake for the little one (which was fine...good but nothing special) and a Strawberry Cheesecake Sundae which was just too much!!! But hey, it's Vegas. It's indulgent. It's over the top.
Maybe because we had just eaten dinner, we were too full to properly enjoy it.
However, i think the kids in our group enjoyed dessert here which is why we really came to begin with.
I'd definitely come back again and get the frozen hot chocolate and depending on the group, try something other than the strawberry cheesecake sundae.