Looking for an Appointment Scheduling Software besides AppointmentCore that integrates with I.S

We currently use AppointmentCore for our automated appointment scheduling, but are looking for an alternative with better features & more friendly UI, but that will also integrate with I.S. Anyone else use a service you’re happy with besides ApptCore?

@John_Barnhart - we use ScheduleOnce for our businesses and all clients. It’s all I recommend. Can’t say enough about how impressed I am with their modern approach to development.