The Dell's wireless is a 802.11g card (so the antenna hangs out and uses up the card slot). The Mac's is 802.11n and is integrated leaving a free card slot.
Oh, and Dell sells this computer for $1900, not $1600.
The specs look close superficially, but dig down and the machines aren't even close in terms of features and performance.
Mathematics is the only science where one never knows what one is talking about nor whether what is said is true. -- Russell