The cart is strong and well made. However, the wheels are a weak point. They are made of plastic. I carried some items about 80-100 lbs and noticed strain on the wheels anytime I would turn the cart left or right. The plastic wheels would lean slightly, which is not good. I think after a while they will probably break. The cart itself is well made and would probably hold up to 400 lbs, but the wheels, I highly doubt it.Also, when carrying items up the stairs, the cart feels very short. I have to bend over quite a bit to grab onto the cart, which is really not good on the back. I wish the cart was taller. It also, didn't feel like the cart was doing much of the work. I was having to lift the weight of the items plus the cart for each step. Going down might be a lot easier with the spinning wheels, but going up with heavy items didn't feel very easy at all.Overall, I was happy with the cart. I think the cart would be really good for moving bulky boxes, but I don't think the wheels would hold up to moving anything very heavy. If you are planning on moving anything heavy, say over 100 lbs, then I would recommend getting cart with stronger wheels, such as metal wheels.