I switched to Amazon earlier this year... Adsense was just painful. Members complained about certain ads showing for them (forever trying to limit issue ads), many ads are just huge and slow loading (regardless of being async), then random people reporting some type of violation to Google, and trying to implement page specific restrictions to suit that. Too hard overall... went to Amazon.
Amazon have done some good work in allowing you to create country specific affiliate accounts, then link them all together as one under your primary country, so you no longer lose revenue outside of your primary country. That is helping.
I get more from donations and account upgrades, than ads. The end result to all members and guests from me, each year, either reach the limit or I close the site. That simple. Every year the goal is reached and the site stays open. I don't care whether it stays open or closes... I place that responsibility onto the members and guests.