There are a ton of apps in the market. One of the challenges is finding the right tool. This is especially true in education since teachers need to make sure the app is kid friendly, links to academic content, provides value to diverse students, and is easy to use in classroom settings.
Recently several ed tech companies have taken on this challenge by creating curation websites that enable to teachers to find and review apps. One of these websites is Graphite. Here you will find reviews by experts and in some cases teachers. In addition to reviews of apps there are also listings for games and websites. I especially like how the Graphite team linked their listings to Common Core standards and provides several features for community engagement such as boards and field notes. Definitely worth a look see.