Dessert Reception: Anyone having/had/attended one?

Like later at night (after dinner hours) with sweets and drinks and dancing. How'd it go? And did you find it cost effective (vs. a more traditional sit down sorta thing). I read something about it as an idea and I was wondering how it works in practice. Trying to help my MOH brainstorm for her own wedding, she'll be getting married in NYC on a fairly small budget.