You can upload all of your own creatives/links. Use Adsense ad a backup if you want and just install the code in a sidebar text widget and control it all from he Admanager dashboard. I don't particularly care for the way you have to set up zones and properties on the Google dashboard, but I've used it on several sites for a while now and it does the job.
I'm considering setting this up for my own sites, so if anyone has any recent experience please chime in. Haven't really used it since it was OpenAds and whatever else it was called many years ago.