There's a question already here which answer this perfectly.
To add my bits, Android Studio is the one which is getting the latest update and is going to be the only official IDE for the future, so I think everyone should move to Android Studio.
Android Studio is far better, stable and lightweight IDE. Eclipse has been crashing on me since I started Android Development, while Android Studio had a lot less crashing. On top of that we have a very good integration of Maven for libraries in Android Studio.
The future is here with Gradle, ANT is a thing of past.