[glial]

That's my question too. I've come to heavily rely on Airflow. As an Apache project now it's becoming mature.

From what I can tell browsing the site, Bonobo looks like it's designed to do data processing within the framework. Airflow insists that it's really a task coordinator/scheduler...however, tasks can be Python function calls. So it seems like Bonobo is a specific use case, where Airflow is the more general case (tasks can be SQL queries, bash commands, etc).