I have the WordPress app on my Android and my Kindle, and I rarely use it on either device. The post editing interface is just awful with hardly any screen space to see the writing, e.g. the Kindle keypad completely obliterates the post editing window when the device is horizontal. Plus, if you start a post on a mobile device, the WordPress app wants to Publish it immediately come hell or high water. I have a dickens of a time trying to save a new post as a Draft and have embarrassingly posted incomplete posts several times. Although, I'm not sure if this last problem still exists, since I barely use the app anymore.

I do agree the app is absolutely great for working with comments, but, alas, my site hardly gets any of those.