I have a 4 post, it works well for working down the middle of the car, everything is open and accessible. The rails are sometimes in the way when doing brakes and suspension work, I just position the car closer to the edge of the side I'm working on. I have a bridge jack that sits between the rails and slides the length of the lift, which is handy. I also built a tray that I can put a bottle jack on and slide between the rails. I bolted mine to the floor. The idea of having a car 6' off the ground and the lift not permanently attached didn't give me piece of mind. I've seen the demonstrations, engineers alot smarter than me designed them, but I bolted it down.