I have two 8X, Ativ S and sold a Lumia 920 I had. The Nokia is absolutely the worst, software wise. The hardware of the 920 is clearly the most advanced, but the thing tends to be a basket case because of the numerous software bugs. The unlocked, unbranded HSPA+ 8X with 16Gb is clearly the most reliable WP8 software wise, with the Ativ S from Samsung being very close. The 8X may suffer a battery drain like twice a month, restart and all goes back to normal. The Ativ S sometimes reboots, seemingly because it looses the carrier signal abruptly. But the battery drain and reboot could also be related to a service that runs itself into and never ending loop. Here HTC and Samsung might have decided to keep going or to reboot. With the Samsung Ativ S I removed my SIM pin, the Ativ S reboots so fast that this way I would hardly miss a call. Then problem wise, some 8X discolor, some Ativ S have their cameras fail. Like all WP8 devices, some reboot all the time cause either the memory or SOC is defective. The L920 ads unsharp pictures in sunlight, dust on the front camera or display, camera crashes while taking pictures, random battery performance, flickering screen brightness, failing touch, frequent freezes (mine had 1 to 3 per day). The Nokia 920 is a joke quality wise. (I am not saying that all 920 are bad, but too many are.)