They are just really well thought out devices. For example my BB "knows" when it's in its charging cradle (and displays the clock and mutes all notifications apart from voice calls) and it knows when its in its holster (and switches from ringing to vibrating). Or on a plane it's easy to make it flight-safe. They're designed from the ground up to be with you 24 hours a day. That sort of thing is hard to describe on-paper but it's why no BB owner lusts after an iPhone (or whatever).