There are a few cons to some promotional items. If you're in the market for a new and exciting item, make sure it's big enough to hold your logo or message. Some are just too small to be effective for some advertising.
If you don't have artwork ready, it can take several weeks to create the artwork, place the order, and then receive the items. Finally, it's up to you to distribute the items, so you should have a good plan for getting them in the right hands once you have them in yours.