Yep, I've heard of Webcomics App, one of the authors of the series that I work for publishes the serie there.
Personally speaking I don't know how we're doing there since I cannot check the app for myself, would have to download it and I don't have any space on my cellphone (which is also a bit old) but I kind of got a bit of info from another artists and even the author of our series.
Payment depends on the contract that you have, compared to other websites you need a specific buffer prepared before they let you publish, but you have revenue available right at the start, not on met conditions like Tapas or Webtoon (People can support you with gems, candy and other types of currency within the app with or without needing to use real money)
Readers usually comments that they want more chapters, but they don't complain about certain topics or character action's neither responsabilize the author for those things, nor call them slurs.
Is not bad, after all is one of the most popular reading apps alongside webtoon, tapas, toonmics and lezhin.