Safe and Reliable
DO NOT jack up all the way w/o a vehicle on it. I learned that the hard way, they need to put this in BOLD on the box and on the switch. If you do end up doing this, just find a bunch of cinder blocks and a few people to stand on it to lower it back down.
Quickjack is extremely safe and convenient. Looking back when I was working on cars with jack stands, it was so dangerous and could've cost me my life. This is the perfect solution for the any DIY'er. I also bought the extension to jack up my Rang Rover Super Charged, lifted with ease regardless the weight rating. My understanding is the 5000LB limit is super conservative.
The downside of this is the weight of the unit, it's super heavy. I think they need to create a lighter version, but just as strong. This is so heavy to move around. I'd pay more for a lighter unit and more convenient storage.