On-screen of software buttons, as I like to call them, are better in some ways. First, they cannot brake (like iPhone button) nor get hardware issues (like l920). They, as in build 10136, can be customized with colors + could be customized to look differently in shape and position, in the future. Then, they are completely highlighted by screen back-light. Brightness is adjustable, not just on off or battery saver mode. In many cases they are positioned better than the too low to press comfortably or too up to look god on the big empty space of the phone.