Edge security and Sourcefire have been nice. Sourcefire was a major improvement over the legacy IDS that it previously had.
Sourcefire has been a great addition. The visibility and control have been nice.
I also like the active/standby HA.
The solution has two separate GUIs and at least three different CLIs (ASA CLI, Sourcefire CLI, and Firepower Management Center CLI). In addition, ASDM plus Firepower Management Center GUIs. If Cisco could stop rebranding, combine all the CLIs/GUIs, and give a consistent experience, this would be great.
Also, AnyConnect is very difficult to manage and use.