My church as a whole is actually using http://www.churchcommunitybuilder.com/ as a directory and it's not that fun to use, although some ministries within the church are more effective with it than others.
I lead the digital video & post production team at my church and we are using a mix mash of Church Community Builder, Facebook group, Google mass email thread and an ugly spreadsheet to keep track of our volunteers attendance, schedule them and communicate the serving opportunities each week. How does the attendance tracking work in your app and would it work for something like this to track volunteers and schedule them to serve?
One reason we have not moved off the CCB platform yet is they have a built in way for the church body to easily send online tithes & donations. Do you have any plans to work that in to your app?
On a side note - I know Hillsong NYC is using this site http://get.planningcenteronline.com/ for scheduling & announcements, and https://pushpay.com/ for payments.
Thanks and again, great job with this!