Display technology: IPS, but different
Both HTC and Nokia implemented an IPS LCD display. The HTC 8X is equipped with a 4.3-inch 1280x720 resolution display with 16:9 aspect ratio. Nokia used a 4.5-inch 1280x768 display with 4:3 aspect ratio. Both screens are about equally high, but the Lumia 920 has a wider screen than the HTC 8X.
Many older apps that were made for Windows Phone 7.5 phones with 800x480 resolution are displayed in full resolution on the Lumia 920, while the HTC 8X will have a small black bar at the top. New apps and the interface for Windows Phone 8 are displayed full-screen on the HTC 8X.
The quality of both screens is very good. The colour temperature of the HTC 8X is a bit high at 7100 kelvin, and here the Nokia Lumia 920 is better with a colour temperature of about 6800 kelvin. On the other hand, the HTC 8X has a perfect sRGB colour range, where the Lumia 920 lacks a bit in blue and red. When you hold the two phones side-by-side the difference in colour temperature is clearly visible. The HTX 8X is a bit blue in grey areas, while the Lumia 920 looks more neutral. However, the colour differences are barely noticeable.
The viewing angles are very good on both phones, but the Lumia 920 suffers less from reflections, as you can see below. The 920 has the brightest screen with 384 cd/m² compared to the HTC 8X with 338 cd/m². Both are definitely bright enough for clearly seeing the screen outdoors.
Nokia's claim that the screen of the Lumia 920 would be brighter than that of any other phone is not true, however. You can see in the chart below that several phones exists with brighter screens. The lack of reflections do make the screen of the 920 easier to read than that of brighter phones, on the other hand.