Amazon is making it a little easier for devs to put out bug-free apps on its Android Appstore with the new Live App Testing feature. Taking advantage of this capability lets you roll an update out to a limited group of testers who hunt for bugs and send usage data back. It's a little more locked down than Google's Play Store beta program, but that might be preferable sometimes.
Developers who want to take advantage of Live App Testing will add the email accounts of everyone they want involved in the test. Participants will then be able to download and test the app on Fire and regular Android devices from the Appstore. These test versions will have access to all of Amazon's services like a finished app would, but they also report back usage data (like crashes) to the developer's dashboard. Tests can be ended or updated as the developer sees fit too.
The service is live in the Amazon developer portal and doesn't cost anything to use. It's probably a better option than testing on just your own devices before distributing to Amazon's store.