There is a product called Shutter ReNu www.shutterrenu.com that will restore faded shutters to look great.

The product used to renew the color of your shutters is a clear and I would think it would do no better than paint. As it is clear the shutter may very well still fade as at least with paint the sun will not get to the vinyl.A premium acrylic house paint will give you many years of service on vinyl shutters.

As I say vinyl is not final.