Presumably one reason for Google developing its own Android IDE is to integrate more tightly with its cloud services. Another notable features is a visual layout designer you can toggle between visual and text modes.
One of the key features is a new build system based on Gradle. It is now the official Android IDE and developers using Eclipse are encouraged to migrate – like it or not. It is based on the excellent JetBrains IntelliJ IDEA. This Java/Android IDE has been in preview/beta since Google IO in May. Google has released version 1.0 of Android Studio.
