Chinavasion is a reliable supplier and offering warranty is good customer service. It will help your products sell as it will give your customers assurance that if something goes wrong with the product, warranty may cover it. If the company will honor this warranty as they promised, note that this is not as simple as it seems so you might want to check with Chinavasion the specific details about the warranty that they provide. Ask them what product issues are covered, who will pay for the additional shipping costs, and the turnaround time for the replacement. As early as now, ask them all possible questions that might be raised later on assuming that one of your buyers will claim warranty on the product purchased.
Hope that helps! Good luck! :)