The service is not quite as smooth as the Kindle own reader. The usual horizontal flip has to be activated and even then the page moves yet in the vertical direction.
The main focus of this app on the processing of PDF files. But I do not need. The corresponding toolbar is displayed by default. If you do not switch off the corresponding functions, you're afraid to change something by mistake.
You can create your own PDF files and how to use a notepad. Who's need ...
As negative I feel bad Android or Kindle-integration. For everything you need its own application menu, which is superimposed on the view and is oddly colorful. Even the list of files used has a colorful wallpaper as a background. This affects about porn moderately. The developers had to heart more simplicity and better integration Kindle.
Search marked Words Kindle dictionary or on Wikipedia / Wiktionary is not possible, but on Facebook. Are you crazy?
Advantage over the built-in Kindle PDF reader are the multimedia capabilities.
In English: Please use standard system colors and remove wallpapers. Nobody Needs page flipping animation. Use system menus instead of overlay menus. Adjust factory settings for Kindle so did Kindle users do not need to walk through all the settings on first use. Remove anything That is not essential to PDF viewing / editing. Thanks.