I have seen pictures of both types that failed. Buying the best quality that you can afford is a start. On a 2 post, you can use a tall stand to give extra safety. Also, I have one piece uprights on my lift. I think it makes it just a little safer. Cost hasn't been discussed, but you don't want to shop for the cheapest. Anyway, a 4 post is more expensive, especially when you buy the jacking plate.
