The new feature lets the user lock a lost or stolen device with a password. The best part about it is that this password can be used to override the existing password, PIN or pattern lock, on the off chance you're silly enough to use a weak one or have it written down somewhere. After all, we all know smudge marks on the screen can give away our best efforts at pattern locks! Even your fingerprint isn't as safe as you'd think.
The more added security we can get on our ridiculously expensive devices the better, in my humble opinion. The pressure being put on manufacturers to include a kill switch has been steadily growing, and Korea has already introduced a law ensuring all devices made for that market include a kill switch. For US consumers in the meantime, this excellent showing from Google means you don't have to wait for OEMs to play catch up.
The only downside I can see is that if you've lost your device in Airplane Mode (for example, to save battery power) then the new lock will only take effect once it's reconnected to the internet, which could give bad guys a little play time with your existing security. In any case, Android Device Manager is available for free right now.
What do think about this new feature? Are you using Android Device Manager yet?