I'm doing exactly the same, I'm using almost exclusively the Kindle app and it works fine on my Boox tablet.
What disappointed me is the slowness of the refreshing. I guess it's because I hadn't used any e-reader before. I bought my Boox with the idea that I could also run other apps on it, since after all it ran on Android.
Running other apps is possible but it's just really a pain, even web browsing is just too slow.
Web browsing on e-ink is widely known to be barely usable, and not what e-readers are made to do. So usage of "even" word is hard to explain here really.
I admitted I didn't have any experience using e-readers before, so please forgive my ignorance. But in defence of me and all the other ignorant buyers, when a device is sold with the argument that it is a fully functional Android device, one might suspect that you'd be able to run some apps on it without too many problems.
This is from the Boox site itself:
> The book is based on the Android 10.0 operating system, which allows third-party applications to be installed on the device and significantly expands the scope of its application
Marketing texts happen to be misleading more often than not. But this exact excerpt you cited looks innocent to me. "Significantly" is subjective, of course, but other than that it's correct.
For me I don't spend much time in those other apps, but it's really nice to have the ability to install Google Drive, GMail, Slack, Notion, Dropbox, and stuff like that so I can easily open up documents that are sent to me through the normal channels I use and never have to worry about actually "transferring" anything to my tablet.
I also keep all my sheet music and academic papers to-read on Google Drive.
What disappointed me is the slowness of the refreshing. I guess it's because I hadn't used any e-reader before. I bought my Boox with the idea that I could also run other apps on it, since after all it ran on Android. Running other apps is possible but it's just really a pain, even web browsing is just too slow.