Free version is annoying
I don’t mind the ads within the app, if I can use the app for free. What I’m bothered is a poor user experience - the ads are often displayed in the resolution that that covers or makes it impossible to press the closing button. It’s usually in the very top right corner, just behind the iPhone’s battery indicator. You can touch however you want, and the only way to get the add of the screen is to close and restart the app.