Android Studioo is the official IDE for Android development, and with a single download includes everything you need to begin developing Android Apps.
The reason why we should prefer Android Studio are :
-Flexible Gradle based build system.
-Build variants and multiple apk file generation.
-Code templates to help you build common app features.
-Built in support for Google Cloud Platform, making it easy to integrate Google Cloud Messaging and App Engine.
-Rich layout editor with support for drag and drop theme editing.
-Hint tools to catch performance, usability , version compatibility, and other problem.
-Official Google Support and usual updates that need no migration.
If you have any doubt, let me know...