I always try to use latest versions of software, including Android versions. So starting from 4.0 to 4.2 there are lots of new very usable features:
1. Expandable notifications. For example when you receive SMS, you can make some actions right from notifications bar. As for DjO it can be very useful to dismiss/snooze alarm right from notification bar.
2. Lock screen widgets. Simply ability to see widgets on lockscreen. And this widgets can be expandable. you can see how gmail widget works. This is very useful.