I don't have kids, but here's what I experienced: On the first ever Villains night it was a crowded mess, where they ran out of food and you couldn't get merchandise. Lines were long. The event was so terrible a cast member offered us free tickets for another After Hours night.
Second try was perfect! It was eerie and super cool to walk down the practically empty streets of MK. We knew to get protien and dinner before the park closed because soda, popcorn, and purchased desserts weren't enough for us from 7pm until midnight. We were prepared for the monorail to stop running before the party ended and walked 'home' to Contemporary. We deliberatly took care of non-after hours rides with Fast Passes before the party started and had minimal lines (20 minute wait tops) during the party. We expected a lot of shops to be closed during the event so we purchased anything we wanted there before hand. All in all, one of the best Disney experiences of my life.