Have the apparat by price. The cheapest versions I had concerns about robustness, professional equipment was too expensive for the intended activities. So me a unit for initially about 70 appeared to be an appropriate middle ground. Thought it was the zeroing of profiled boards with brackets. The first unit after a day the seal was leaking behind the hose connector, after three days of complete release mechanism fell apart. Equipment has been reclaimed and easily replaced with a new one. Also with this device the gasket was leaking after a few hours and I've replaced it. After the device is functioning, but fell after processing of about 20 m2 of boards again, because the air pressure was not allowed to pass. The processing of the device looks quite out of solid and it is also very comfortable to hold - but unfortunately it is constantly broken. From my experience I would say that it is unfit even for occasional home works stylus. Maybe I've also had only twice unlucky!
