[hamidpalo]

Genymotion is absolutely amazing. Not only is it super fast but also has images with Google Apps, which are almost impossible to get on an emulator.

The downside of using Genymotion is that it's so fast it will hide a lot of performance issues that you will see when running on an actual device. So please, test early and often on actual hardware with extreme amounts of data.

[ZoFreX]

+1 to your performance advice - my x86 images (both through 'emulator' and Genymotion) are actually faster than a real phone.

For performance testing I recommend using a Galaxy Ace (actually using - install some apps, fill it up with data) and testing your app on it. If it's fast on that it'll be fast on just about anything!