The greatest feature in Aruba ClearPass, in my opinion, is its modularity and its openness to all vendors. Unlike its competitor (Cisco ISE), Aruba ClearPass supports integration with almost all vendors, and the ClearPass Guest module is unmatched by any other vendor.
The ability to tune small details is really powerful and is always a selling point.
Of course, let's not forget that the ClearPass Insight module which produces such valuable reports with small pieces of configurations is a great feature.
Improvements to My Organization:
Customers who have used ClearPass had their organized improved with the ability to control all devices connecting to their network and the ability to even form a database of all the endpoints in the network and their fingerprints as well.
Also, the integration with Aruba Wireless is always a plus point.
Room for Improvement:
The main issue I have seen with Aruba ClearPass is specific integration with Juniper firewalls, and this is definitely something I would like to see in the future.
I've had no issues with deployment.
I didn't encounter any issues with stability.
I didn't encounter any issues with scalability.
I would advise customers who want to protect their network, do health checks on BYOD, provide guest access and of course AAA functions to manage their network devices to go for ClearPass, but they have to be ready to get into so much details as the power of ClearPass is in its ability to customize even the smallest details as they wish of course.