I was in the same boat an year ago and picked Airwatch due to it's capability of managing other platforms. If you are looking at managing only Mac OS clients and don't have to any thing to do with other platforms (Windows, iOS, Android, etc.), JAMF is the way to go. To answer your question specifically, custom scripts can be pushed to Mac OS clients using Airwatch as well. However, JAMF brings more flexibility and custom handling as it is dedicated (almost) for Apple devices.
Again, I strongly suggest considering the Unified End Point Management capabilities of Airwatch before making your choice. Most of the times organizations have to deal with multiple device platforms, and maintaining multiple management solutions may not be an ideal situation considering the buzz around Unified Endpoint Management lately.