Interstitials and banner combo

For a non game app…which ad network works best with interstitial ads? I plan on using banner and int. From admob…but is it better to use appnext int. And admobs banners? Which combination would be better

I get equally strong eCPMs with Admob as I do with AppNext, StartApp and mobileCore. Admob has the highest fill-rates though, but not by that much.

The best approach is to use more than network per app so you get an array of ads.