Few points that could be better
When creating a new add the form should not be in a lightbox like window. I just installed your extension on a website where we have numerous ads groups (like 100...) and we cannot see anymore the save button at the bottom.
I had to add a submit button to your code on top, so he can save it. So it would be better if the creation screen is in a new window as when we edit an ad.
A button to reset the stats for an ad would be a nice addition too.
UI has been updated to match EE CP. Reset Stats button has been implemented. Version 1.0.5