AdSense isn't hard to beat on performance. It's main strength is it's ease of use not raw performance. The company I work for offers full service ad management. We generally use a combination of header bidding, Exchange Bidding and Google AdX (I wouldn't call us a "programmatic company" as the demand is not our own - we hook publishers up with all the best partners. That includes Google as we are GCPP). We'll generally beat AdSense by a very healthy margin, even after our own revenue share. I wouldn't say though that we could do that every-time for every site.

We won't sign very low traffic sites. Our solution is labour intensive on our part, so we need a certain volume to warrant the work. We will also generally stick with AdSense on any units that have an unusually high CTR. Because we work on a CPM basis it can be hard to compete against CPC on very high CTR units, plus high CTRs are often indicative of inventory quality issues. There are are also one or two geos where I'd expect us to offer a lower margin above AdSense. Otherwise we'd expect to out-perform it by at least enough to make it worthwhile for both us and the publisher.

matbennett,

Can you tell us where does adsense perform better than programmatic or waterfall stack?

Adsense is designed to be automatic and easy to use for everyone, so you can focus on creating content of your website to boost the traffic. but Adsense is actually the last floor in the waterfall of programmatic.
A programmatic company has PMP deals (it's like direct deal from your advertisers, but instead of dealing with advertisers by yourself, the programmatic company can help you to do that - of course we need to share the revenue with them but it is still better than Adsense).
And other optimization which potentially higher than Adsense.

It depends on your traffic geography and your categories but in my opinion, it is necessary to make change on your ad layout (testing some ads from other company and has comparison). For the question of the topic, we cannot know which is better if we don't try.