From 2 years I am using Nokia lumia 520. I am thinking that microsoft had launched thia mobile in a hurry and it forgot to add and improve some basic stuff like Ram just 512mb for smartphone and that to windows os. The internet explorer didnt work properly with that ram.
Any other browser doesnt run for long time due to less ram. More problems occurs with Youtube videos.
The sound quality is also not good. During calling as long you are speaking it is giving rush sound.
The only good thing about this phone is camera. Though it is just 5mp but gives competition to other mobiles of same range cameras. the design of this smartphone is good.
Some good apps for this mobile which even work with low RAM. Due to windows os it is easy to handle compare to android ones.
Battery back up is also good . Almost lasts for 8 to 9 hours during calling.
But this mobile doesnt fit into rs 6000 stand due to the fact that microsoft deliberately kept the RAM low in an experiment to match with apple smartphones.