The ability to create campaigns very quickly with ease was really helpful when we didn't have much time for testing! I wish it could be easier at times but most things aren’t too hard once you get used them (and they are extremely well documented). We were able test different approaches without wasting precious resources or spending hours creating new content each day/week etc - so that saved us tons over what would normally take months!! There isn´ts anything i dislike as such about impact just some minor issues here an there which can sometimes make life difficult if not familiar enough wth how everything works though these do go away fairly easily however overall its pretty good.