The Lenovo Thinkpad X220 Tablet has a "one way only" rotation system and no "securing latch". The mechanisms are different than the previous generation which is the X201 Tablet.
The positive aspect of one way rotation is that the machine will train the human to rotate it one way only. (hahaha) This rotation mechanism might be simpler and sturdier than the more "loose" both direction system. You cannot by "by-curious" with the X220T. ;-)
The securing latch is something that most people won't need. Removing that latch allows for easier transition between laptop and tablet modes. For the "hardcore running around" type person this should be a concern. If you for some strange and weird reason have the screen facing down you will notice that the system opens little by little due to screen's weight + gravity. Shake the money maker and the screen will open a lot.
I hope the video and my little details aid your decision making power to BUY the X220 TABLET. I have to figure out how to make subliminal messages, and trick you ;-) muahahaha.