[sahaj]

One problem with Amazon App Store on Android phones is that if I replace my Android phone, I have to start all over again. Using the Google ecosystem, it's a matter of signing in and all my backed up apps and data are reinstated. There's a lot more friction to keep using the Amazon App Store/Underground app than there is with Google Play Store.

[grogenaut]

untrue, you re-add the amazon app store and your apps are back. Google also recently changed it so it doesn't force reinstall everything, you choose what you want re-installed. Or at least it did in 5.2. I actually prefer it as some apps are garbage