The PQLS on the 1120 is for all channels, on the 1020 is it the stereo mains only. Note that PQLS only works with compatible Pioneer Blu-ray players.
The video upscaling in the 1120 is FAR superior to that in the 1020. It's the new Marvell QDEO chip that's contending for the crown from Anchor Bay. If you're using analog, or any HDMI source less than 1080p going into a 1080p display, this could be worth the difference right here.
The DACs in the 1020 are from Wolfson, the 1120 uses Burr Brown. Burr Brown is a little more respected by the audiophile community. Not sure if the differences between them are audible, but they can be shown on laboratory equipment.
Also note that the 1120 is 17" deep vs the 15" of the 1020. This is due to the better amps, but may be a drawback if your space is limited. It's also a half inch taller, and 6 and a half pounds heavier.
