try AdX and use the backup tag feature while creating an ad zone, give it an eCPM you expect to get and paste your code. If they can't meet your CPM average they'd automatically show whoever you picked as a back up ad tag (Exoclick's ad code etc)
Then you can go compare them with whoever you picked as back up and see who's getting you the best eCPM or total earnings
On one of my sites I got $0.05 per click average with AdX and around 0.45% ctr and as high as 0.8% CTR on some placements
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