The advantage of ZÆD over other devices in the market lies in the following factors:
Active Belaying for soft whipping
for climbers and belay partners, the process feels like climbing with a partner of the same weight category. Other brands' devices lock abruptly, which means that you are generally not belayed softly and hit the wall quite hard.
In our tests with another device, it was possible for a 50 kg belay partner to remain almost motionless on the ground when an 80+ kg climber fell. Some rope teams may see this as a safety gain - we see it as a major disadvantage for sport climbers who want to whip often and softly - ZÆD now offers these rope teams soft belaying as an option: the belay partner is pulled towards the first quickdraw, but is braked safely.
Fast rope delivery for clipping
Other devices block the rope even when the rope is pulled up quickly by the climber. This makes it extremely awkward for sport climbers to clip quickly in shaky positions. ZÆD allows the climber to retrieve the rope quickly without blocking the device.
Adjustability of the resistance
ZÆD can be adjusted in intensity to the weight difference of the rope team. If I am climbing as an 82 kg climber with a 50 kg belay partner, I can do this with level 2 in the same way as with a 65 kg belay partner in level 1 - in each of the cases described, both belaying and falling feel the same for those involved, namely as with a rope partner of the same weight class.
Works in steep overhanging walls
ZÆD's level 3 configuration is designed to support lighter belayers and the climber even in steeper terrain where the device usually couldn't flip up to provide friction (there's a solid wall up there, right?). Level 3 doesn't need the full flip upwards to provide friction, this allows ZÆD to be suitable in up to 55 degrees overhanging walls. Climb hard!