The ability to create custom reports, drill down into accounts/subscriptions for further analysis or actionable insights from our data sets were some of my favorite features! It was difficult at times using AB with multiple people within one account as it could be time consuming when trying figure out who did what actions etc..
Also having all your billing information available would have been helpful so that you don't need separate systems like Acrodoopee which requires additional monthly fees (which we didn’t want). We used this tool primarily during campaigns but also had use cases where they helped us understand how much revenue each channel contributed vs overall spend per customer segment over various periods - allowing me make more informed decisions about future campaign strategies without needing external consultants / 3rd party services such as Deltek's ROI reporting feature set.