We have CA APM running on a few of our major applications and it has allowed us to get more in depth understanding for these with incident and problem diagnosis. Without this we would be left going through logs and not being able to see real time events and behaviours of our applications. This has also allowed us to see performance issues after upgrades and focus on specific areas rather than looking across all components.
The workstation interface is very user friendly and the abilty to create custom dashboards and alerts is great. CA APM is a tool that should be a must in current IT environment we live in.