A roller skid with poly wheels is beneficial for rigging projects that require care for the floors. For example, poly wheels do not leave marks on floors and they are good when conveying loads over wood, ceramic, or (clean and smooth) cement floors. It is highly recommended that loads not be left resting on poly wheel roller skids for days at a time since over a period of time the poly wheels can compress and incur “flat spots”. This will then make it difficult to roll. A roller skid with roller chains is beneficial in that they are more durable and handle heavier loads. Loads, for example, can rest on them for weeks and months at a time without causing any damage to the roller skids. In addition, roller chain roller skids can handle more uneven terrain as opposed to the poly roller skids. One disadvantage which is very important to point out is that they can potentially damage floors. If you are moving on floors that you don’t mind scratching or possibly gouging then the roller chain roller skids are a great choice.