I've owned this floor jack for about 3 years now. Has never let me down. However, the only downsides I can come up with are the limited height and the touchy release valve. I can't get the rear of my Accord high enough (using the tow hook) to get some jack stands underneath it. As far as the release valve, it is easy to open it too much and the car may come down too fast. Other than that it was a great buy and has already paid for itself with the amount of work I've done with it.
The day I bought this jack I used it on concrete to lift once corner of a 3500lb car. The jack is said to be able to lift 4500lbs total. The entire jack bent horizontally. I immediately tried to lower the car but it was bent to bad it wouldn't lower into place properly to get out from underneath the car. I had to re-lift the car and pry the arm back into place with a screw driver as I lowered the vehicle in order for it to collapse properly.