Overall I love this jack: it's simple to use and maneuver as well as being easy to control, especially when lowering a vehicle. It's light compared to hydraulic floor jacks, especially when compared to floor jacks of equal capacity.
What I think needs work is the metal alignment tube inside the bag. When lifting a vehicle, you're lifting in an arc. This bag wants to lift straight vertical, any movement from 90 degrees makes the tube inside bind up when trying to lower the vehicle. This binding causes jerky movement that could unsettle the vehicle on the jack.
Another thing I wasn't very pleased with is the handle, it's very short especially for tall people or people like myself : a tall person who is also a high level amputee and uses crutches to walk around. The handle is also uncomfortably thin where your hand grips.
Overall I love the jack and do not regret buying it. I use it daily and will modify it as best I can to suit my needs.