Did you see a substantial increase in your revenue with their suggestions?
I saw an increase. They made a suggestion on layout that I just did not see because I was so use to looking at my layout. That being said, their suggestions are not gospel. You need to use common sense and test. But it is nice to get an outside view.
But beyond that, having them look can alert you to potential compliance issues and also give you a point of contact if you have an issue that gets you in trouble later.