Sometimes the simplest apps are the best and Who’s In? tackles one of the biggest problems in making plans with friends / family. A simple who’s in? text notification can be sent to friends and you are either “in” or you’re “out” and its as simple as that.
My initial reaction to this app is that it is beautifully designed and very simple without being simplistic. I think the ability to declare immediately that you are “in” or “out” of going to attend an invitation should be handled as such without the need for any complications. And for that reason I give this app a thumbs up.