It installed instantly but when it came to setting up the banners I had trouble. I struggled with it for a while assuming the problem was user error but at the end of the day, I submitted a support ticket. Half a day later, I got a response. It turned out that Ad Agency was not working on some pages due to a conflict with another component which I use to create a business directory (Sobi2). The tech support fixed the problem and explained what action was taken so that I would understand it too. Surprisingly, the action taken by the IJoomla team fixed a long standing issue I was having with the Sobi2 component as well! I couldn't be happier.
Ad Agency has a LOT of features so it might take a couple of days for the average Joomla user to get used to how it works but know that if you run into a problem, don't struggle as I did - submit that support ticket. These people are serious about support and will help you out in a timely and professional manner.
I couldn't be more pleased and for me it was worth every penny.