I had my 30th at the Stanton Social. While I was a little nervous given the mixed reviews, it turned out really great. There is a mezzanine that we had to ourselves for a party of 20, it was a little tight, so 15 would fit more comfortably. It was $45 per person for food, and it was a lot of food. Quite a few choices to create a menu from in advance and its all served family style. Most of the food was good to very good, some just ok. Nothing was bad. And our waiter took great care of us. While I don't know if I would go there for dinner on a regular night out, it worked out great for this occassion it was a big hit with everyone and we had a great time.
And it certainly can be described as hip.
If you are not interested in a private room, try Perry St. I had booked a table for 12--essentially, they were going to line up two toppers in a row--maybe they can do more.
Can't give feedback on the actual experience. We had to cancel the dinner.
Rosa Mexicana??? We have had fun times for large parties.
It's hard to get tables for even 12 sometimes.