[dsraven]

when I worked in an auto and truck shop we had both styles. the 2 posters work great for doing ball joints or whatever because the suspension parts are open but I have seen vehicles fall of 2 posters, never a 4 poster. the guys would lift trucks just off the ground to get the wheels off because they were afraid of it falling off. hard to balance a truck compared to a car. I always thought the job could then be done on the floor because thats how it looked anyway, except the hoist lifted the truck quicker maybe, still using stands under it though. the 4 post would be the one I would buy personally, but that's just my take. it sucks to see a vehicle fall off with the life hazard and damages to things. that said, when the 2 posters got into trouble they were usually being used for something that was a bit iffie anyway. like a truck heavy on one end and light on the other end is a hard thing to get on there and have it "balance" when you are pulling and pushing and hammering etc on the front end, or if you plan to remove weight, like a rear axle, then you gotta plan for that or maybe do that job on the floor. I always tried to use the 4 poster because it was easy and quick to drive on, do the job, and drive off. I was also used to working on the floor so working around the platform didn't bother me much. the hydraulic trolly jack was awesome and had a built in set of stands that were great too. you could easily fab a set of "drop on the rails" style of stands if you needed some and didn't wanna drop the cash for another hydraulic trolly.
just my 2 cents. my shop isn't tall enough for a hoist so I carry on with a jack and stands. maybe next time.