The overall construction seems sturdy but the devil is in the details. The reason I bought this was the range of lift. Any scissors lift that could get down to 6.75” off the ground (4.7” is BS) and up to 57” (if true) would cost much more than $550. But…as with most non-domestic mechanical items, you’d better be prepared to make adjustments/modifications to get it to work as promised. So if you’re not mechanically inclined, look out.
Check all bolted connections. Some were intentionally loose because they had to be removed for final assembly (aluminum parts) but others should have been tight (winch-to-frame). One small red wheel was missing a spacer washer and the insert collar to prevent over tightening the wheel, was deformed on one end. The aluminum parts (u should file the razor sharp edges to avoid cuts) must be removed from the lift carriage to slide it into the frame. My unit binds at two locations along its range, which makes the platform tilt a bit at each. I have not figured out the cause yet nor if I can fix it. It “may” break in and be fine. I can live with it if necessary. One design flaw… the unit has four red wheels that allow it to work in a horizontal orientation, but the crank handle will contact the floor before the small red wheels. I removed the black plastic handle, cut off the smallest segment, shortened the bolt and reassembled. If while vertical, the crank handle is left closest (down) to the big wheels before laying the unit down horizontally, the handle will not hit the floor. Not so if oriented up. Winding of the cable is another whole issue that you’ll have to deal with. Wheels are of high quality. I did not receive any instructions what-so-ever. But if u need instructions, u are already in trouble.
Assembly should be obvious. Over all, I am so far happy with the purchase. Good luck.
Jim Surra 
