For what it's worth here (i am not very experienced in 4x4ing), i loved the flexibility of the mechanical engagement of 4-wheel-drive, manual-locking front hubs, and driver-selectable rear and front diff locks. For example, reversing a trailer in low range, while in two-wheel-drive, provides unbeatable low-speed control; in the same vein, locking the rear diff and putting the box in low range just to walk out of a soft spot (without locking the front hubs, a bonus situation when that allows me to not go outside and lock the front hubs when it's -30C), i find is fantastic. But i've never had air lockers.