Unfortunately they've taken a left turn on the quality front, at least for the iOS app. It was unmaintained and slightly buggy, but then it became maintained and slow, power-hungry, and extra-buggy, and new versions usually don't make it better. At least the macOS desktop app is still based on WebKit rather than Electron, so it doesn't guzzle battery.
They've added some handy features, and there are more in the pipeline, but the current mobile experience is so bad that I'm having trouble not looking at alternatives. This despite the threading and content model (inbox divorced from chat is amazing) that has kept me very loyal for a very long time.
