no Amoled lcd. no corning gorilla glass, processor is only 1ghz. battery is weak. y gsm gave it 10 out of 10 to this device??
So the difference will be on the ram only and the support for nokia pro cam beside better IPS display rather than the standard LCD of Lumia 520...seems ok but not the one I imagined...still 520 is one of the best devices for the WP OS ever :)
while the only major upgrade besides Windows Phone Black is the 1GB of RAM, the 520 is the best seller out of all the Lumia's. Here's the video: