How are your iAds performing?

I'm now seeing various iAd advertisements across numerous iPhone apps. Most suck. The banner strip works better than competitors, like Google. But after that, for most there is no discernable difference in ad content or quality for the standard ads. The high-end iAd promotions are a different scenario.

So sayeth the user. What about from the standpoint of those who create iAds and, better still, those who are compensated by them.

Any app developers out there ready to provide info on:

1. cost and effort in creating an iAd advertisement, versus using a competing tool
2. what kind of revenues are you seeing with iAd?
3. how do iAd revenues compare to your other solutions, if any
4. does it look like iAd revenue will let you support free apps?

iAm interested in hearing your stories.