NIA classes, anyone?

I have a membership to a club that offers NIA classes. I've never tried one and the sample classes on YouTube look rather silly to me, but all the reviews that I read so far have been exceedingly positive.

Has anyone tried a NIA class before? What did you think? What kind of person/goals would it be suitable for? I need to lose weight, and I prefer fast paced classes. I would like to get into yoga, but I get very restless in class, so NIA sounded like a decent alternative.