Pros The camera is phenomenal. Its 3G/4G reception is far better than USB dongels (tested in the fringe areas of Globe Telecoms in the Philippines), It worked where dongels did not.
Cons Short battery life, it can get too hot to hold when used in the tropics.
Summary With this phone, I do not need a fancy camera nor a tablet. I love my Lumia. Having an 820 is IlLumiating experience. Kudos Nokia!!!!
Cons Very poor battery
Image quality not sharp for a 8 MP camera
Call quality is poor
Does not detect micro SD card often
Windows 8 apps limited ( but has scope for improvement)
Summary Overall , it is a very okayish phone. Bought it only because I had a free upgrade ( Used iphone 3Gs before). Now I feel I should have bought something else. May be an Android phone from Samsung or HTC.
Pros * Nokia's own apps (HERE Maps, HERE Drive+, HERE Transit and Nokia Music) are outstanding
* Excellent performance of Windows Phone 8 interface and apps
* Wireless charge (although a new cover needs to be bought)
* Support of micro-SD card
Cons * Average screen with low resolution compared to other devices
* Some apps are still missing in Windows Phone 8 app store
* No notification LED
Summary Compared to the Nokia Lumia 820, it lacks some of the key features such as a high resolution screen, wireless charge out of the box and OIS camera. However the performance is on par, as the CPU and Memory are the same, while the price is much slower.
Compared to HTC Windows Phone 8X, the screen of the Nokia Lumia 820 is worse but it allows to insert external micro-SD cards.
More info can be found at this analisis Nokia Lumia 820: http://www.teknofilo.com/nokia-920-analisis-y-prueba-a-fondo/