There are a few things to keep in mind when working with a product videographer. The first is to make sure that you are clear on what you want. Be as specific as possible in your brief, and don't be afraid to ask for examples of their work. It's also important to be realistic about your budget - good product videographers don't come cheap, so if you're working to a tight budget you may need to be willing to compromise on quality.
Once you've found a videographer you're happy with, it's important to build a good working relationship. Be clear about your deadlines and expectations, and try to be as flexible as possible on their behalf. They are, after all, the experts. Trust their judgment and you should end up with a great final product.