Earlier in December last, Google announced the start of a beta test for Google Audio Ads. The beta has been going well and, in fact, the Audio Ads Team is looking for more testers. In terms of feedback, the Audio Ads team has heard that beta testers like the simple and clean user interface and the targeting and reporting options. Beta testers also find the audio ad creation process easy and fast since it only takes them a few days to create their ads and launch their first campaigns (as compared to potentially weeks for traditional radio ads).
Advertisers who are interested in participating in the beta can sign up here.