While the Samsung is an LED (Backlight) it is still a TN panel. The Dell uses a much better panel - the IPS.
I was just in the market myself, Bought the Samsung LED 32 In LED 1080 P 120 Hz($550). But the ONLY reason is the Dell did NOT have the connections I required - Two computer inputs (Using HDMI) and a Stand-a-lone DVD recorder (W/Cable input). The U3011 would have been a excellent choice but at $1300 was a pass.
quote new PLS (Plane to Line switching) panel that has characteristics of the IPS panel technology End quote.
I'll have to research that some more, My gut felling is that it's an inbetween the two.