The green tinge you mentioned is a bug in many lumias after black, try searching for it, there might be a solutions somewhere, its fairly widespread. And frankly, lumias are superb devices, just that 820 has got a ridiculously small battery, so its not nokia/wp 's fault. Most lumias perform pretty well. My 520 has a smaller battery, and with full brightness,2g, double tap to wake, location, WiFi, and lots of usage, it still lasts more than 10-12 hours, and it can run for 20+ hours even. But 820 is a big phone with small battery, so understand...