...Didn't take long for them to completely ruin your app. Good job on selling out at least! Hope the $$$$ was worth ruining your reputation forever...
I bought the paid version within about an hour of trying it out, so the [presumably MobiSystems driven] decision to plaster the free version with adverts doesn't affect me [nor would have had I been using the free version, as I'm rooted and block ads at the hostfile level].
I've got to say though that [following the debates on here and reading the comments on Google Play--and MobiSystems nauseating copy/paste reply to them all], I'd not even have downloaded the app to try in the first place, if I'd come across it nowadays.
When are developers and site owners going to realise that people who hate adverts are never going to click on them in the first place and the more you force adverts in their faces or [in the case of an increasing number of websites] try and force users to turn off adblockers, the more determined those users become to NEVER click on one of your adverts. So nobody wins:
The developers don't get increased ad revenue as those users don't click the ads. And the users begin to dislike your app and distrust you and possibly consider moving elsewhere.
No one begrudges developers making a living by monetising their apps --especially an app so good as AquaMail. But I don't see what's wrong with using the method of adding extra features to the paid version, where people will pay to make something good even better. I think, when I tried the free version, it was limited to one or two email accounts and, after trying it and finding how good it was, I willingly upgraded to the paid version, so I could use it with my half dozen or so accounts.
Plastering your free version in ads and then asking people to pay to remove them is like a restaurant serving up a meal smeared with dogshit and then telling you you can pay a bit extra to have the same thing without the turd on top.