First of all, pay a little more and get the 2 ton jack. It has dual pistons and is built a little better.
Secondly keep in mind that a Rapid Pump Jack such as Harbor Freight sells, also comes down in a hurry. I dropped my car and crushed one sides exhaust even though I was trying to let it down easy.
Costco used to sell a excellent aluminum jack made by Alcan, but I don't know if they still sell them.
Lastly, as with all Chinese junk, retighten every last bolt, lube everything with WD40, and here is one more tip: one of the guys at H.F. said you should always raise and lower the jack a couple of times with no load on it to purge any air out of it.
Keep in mind the guy who assembled it probably boxed it upside down!