In comparing Google Play or Amazon AppStore, they both have their advantages and disadvantages. I have found that Google Play will upload apps right away, whereas Amazon AppStore has a lengthy approval process. Amazon AppStore approval process is great for weeding out junk apps. Amazon has also developed an emulator that allows users to test basic apps before downloading them. However, developers cannot submit an app revision until the app (or prior app version) has been approved. As a result, it could take up to two weeks to get changes submitted and approved. On the other hand, Google Play Google Play will post the most current version immediately.
If you want the latest version of an app quicker, go with Google Play. If you don’t mind waiting a week or two for the most current version, then go with Amazon AppStore. They do a fantastic job of testing apps.