Firstly, great job getting this out!
This isn't really priority, but I think it would help my staff if you duplicated the "Target Criteria" dropdown boxes section to replace the Button URL textbox.
E.g. you use the dropdowns to select who needs to see it, and then you also go through and select where it should lead to from the dropdown boxes.
Selecting "Custom URL" from the first dropdown would then display the "Button Link" text input.
Hope that makes sense.
It's great as it is, but I think this would be more user friendly.