newbie developer here

. I'm building a navigation-based app, and part of the functionality is to allow people to upload and retrieve sets of locations (consisting of a set name, location name, and a pair of coordinates) to a database accessible by all users. I havent done any database programming or back-end work before but have heard that Google App Engine and AWS are two good choices. I've decided on App Engine's Datastore for now, and just wanted to know if other people have used it before and if its compatible with iOS apps. Thanks!