Here’s an interesting option for Android phones. As long as your phone is in your hand or in your pocket, it stays unlocked. That way when you want to quickly pull it out and scan it for new messages you don’t have to enter your password. (This feature is only available on newer Androids with 5.0.1 as part of the Smart Lock feature set.)
The feature is called “on-body detection.”
It will disable the lock screen until you put your phone down on a counter or a table.
It’s not quite as secure as locking your phone after 20 minutes of inactivity. It uses the built-in accelerometer to determine if it’s moving around. So, if a pick-pocket steals your phone it’s unlocked. (It's much more likely that a thief will grab it from your hands while you're looking at it...)
I use an iPhone and I love the quick fingerprint unlock feature. Do you use this or other biometric security features on your phone? What has been your experience?