I earned my money back on my Z9-Mini within three weeks.
Bought it with LTC and mined on Mining Pool Hub, auto-exchanging back to LTC.  LTC now isn't worth as much in fiat as it was then ($160/LTC) but I did earn back my initial investment, coin-for-coin.  Of course being lucky with a first batch helped.  Anyone ordering a short time later was S.O.L.  Not saying the manufacturer is greatawesomewonderful (I think their marketing practices are borderline criminal), rather highlighting alternative thinking in regards to return on capital.  Mining returns need not always be measured in USDollars.