I like most about priority engine is its capabilities to track our prospect leads across multiple channels (Email, Social media etc) in such a way that we can easily filter all the data. We also use it for marketing campaign management, hence, I feel its best suited to manage email campaigns. Nothing at this point, it is working well and we are satisfied with it. If you want an all rounder tool then go ahead otherwise have a look at the features in detail and decide accordingly. It helps me understand which channel of communication would work better, based on the behaviour patterns of my target audience.