I like that they are very flexible when it comes to working together as we have many teams at our group.
They take time out of there day for us sometimes if needed and can be contacted during office hours or even after work hours, which helps keep them connected while away from home. There isn't much I dislike about IA interactive but i would say not being able to pay invoices online could improve my experience. We use them mainly where we are creating campaigns for Google ads so this saves us quite a lot of time in comparison to having to create all our own content etc.