Saw a working model of the Lumia 925 today. Great screen - even better than that on my Lumia 920. I did a comparison and the colour on the 925 is much more vibrant and vivid. The lumia 920 is no slouch as far as the screen goes either.
That is due to the 920 having an LCD screen and the 925 having an OLED screen. I had an 822 and a 920 side by side and like the 822's OMLED screen better, its a lot brighter and vibrant although as a phone, the 920 is better overall. I hope they trash the LCD for the OLED for all of their future phones.