Definitely prefer the T shaped connector, I've used the plastic original, the L shaped and the rMBP one. One of the things I liked about the MagSafe was that if you tripped on the lead it popped out. I have dealt with plenty of calls where customers have tripped over their lead on a Windows laptop, it's fallen and the laptop has got damaged (usually the screen).
The L-Shape connector does not have this benefit if caught from certain angles, the MBP will get dragged backwards. This defeats the whole purpose of the original design, so I'm glad they've gone back to something similar.
The L-Shape connector does not have this benefit if caught from certain angles, the MBP will get dragged backwards. This defeats the whole purpose of the original design, so I'm glad they've gone back to something similar.