Some people are pretty excited about Android Studio, and while it may present a few hurdles for developers coming to it from more familiar IDEs like Eclipse, features like the following present solid arguments in its favor:
This is a screenshot of Android Studio's layout editor (taken from an Android dev pro tip from Jamal Eason and Katherine Kuan) in which simultaneous previews of a responsive app appear on differently-sized screens. It's pretty simple to set up:
Click on the overflow menu button > Preview All Screen Sizes. You can switch between landscape/portrait orientations too. If you want to look at a single device, you can make a selection for that as well.
Unfortunately, now you can't just pretend everybody has the same size screen as you.