I have a experience about nokia lumia 520. This phone’s bettery backup is too good approx 7 hours if you are countinuesly using whatsapp and facebookmessenger and nokia lumia520 don’t have front camera. Even I have a great experience in skype video calling usging back camera. Nokia lumia 520 is also upgradable for windows 8.1( lumia denim) multitasking performance is average in this phone overall nokia lumia 520 is good choice for daily ruff and tuff use.