Ad networks to replace Admob

[a11111]

Now that Admob has changed their House Ads model, their network has basically gone down the drain. Their old model allowed you to create ads to your own apps/offers that would display 100% of the time when Admob didn't have an ad to fill the slot. Now, you're not allowed to do that anymore, and since Admob's fill rate is nowhere near perfect, you often see a blank white space where the ad should be because for some reason they decided to remove the option to show House Ads whenever there are no other ads to display. The new model allows you to set the number of impressions you want each House Ad to get, but it doesn't seem to be able to show them only when there are no regular ads to serve.

So I'm wondering if anyone has tried out any other networks (please don't say iAd lol). Let me know what you would recommend using and what you'd recommend staying away from. I did sign up with Mobfox because I've heard some good things about them.