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.