The Zero promises excellent portability, useful features, and a decent capacity.

I already own the Skywatcher AZ5 but had good reason to believe this would be an upgrade. In practice, it met my high expectations and proved to be an upgrade over the AZ5 in most areas. I primarily compared the mounts on a sturdy carbon fibre tripod, carrying a Vixen SD81S loaded to ~4.5kg.

First, the Zero is solidly made with smooth operation. I often feel that there’s a little play inherent to the AZ5 but the Zero feels precise. The finish is good but not quite premium.

Portability is incredible. While the AZ5 head is only a few hundred grams heavier, it’s harder to assemble in the field and is a larger, more awkward shape. Furthermore, the Zero folds down neatly, clearly showing the thought put into its design.

It is capable of both free movement and slow motion without clutch adjustment. Operation is very smooth, lacking the stiction found in the AZ5. The slow motions take more force to turn than the AZ5 but are smoother.

The capacity of the mount is rated at 7kg. I think it’s fairly accurate. It’s not rock solid and does wobble slightly when focusing but is still a noticeable step up from the AZ5. Stability varies between scope designs but I would say a 100mm refractor is probably the largest I’d be happy to use on the Zero full-time.

The Zero also comes with weaknesses. The clutches can’t be locked. This demands some caution if you like to move your rig in one piece. Balance is critical. Even tightened fully, the gears can rotate, and your scope will swing down if unbalanced. Like the AZ5, slow motion will not work if balance is too far off.

Finally, the price. While it competes in capacity with the AZ5 and Porta II, its price is a level above. Even the Japanese price of ~35,000yen is fairly expensive. The same money can get you a Stellarvue M2C for example. That mount is rated for a much greater capacity but gives up the slow motion. For its price, I would recommend the Zero to those who know their needs well.

Advantages: extremely portable, well built, decent capacity, offers slow motion controls.
Disadvantages: high price in its class, clutches cannot be locked and balance is extremely important.