It's a small detail, but an important one. I completely disagree with everybody who raves about the importance of the mag-safe connector, I've never had a problem with the standard round port connector of my pc's, but this design is a huge improvement.
The advantage to the mag-safe connector is not evident at first. It only becomes evident when one day you are using your laptop while it is connected to the power cable, and someone else trips over/steps on/moves a chair in a way that eventually yanks on the far end of the power cable. Only once you see that happen in real life (to yourself or someone else) do you truly appreciate the advantage of the mag-safe connector.
I firmly believe in MagSafe.
That might be easy to figure out on a laptop but on an AC-charger? A workstation? A lot of ports are sideways.
And, the ports on my monitor are, by any conceivable scenario, rotated 180 degrees from what they should be (they are on the side and "up" in that scenario is facing away from me, towards the wall).
Stuff like this requires consistency so that you can trust your instinct, USB have failed miserably in this regard.
And the Apple dockplug is even worse IMHO; besides looking near-identical on both sides, the cable with my iPad 3 printed the logo so lightly it's quicker to guess vs. trying to find it.
Also, I don't understand why people always applaud the use of micro-usb. I have NEVER seen a single plug that didn't lose its ability to hold onto the slot after a month or so.