I wouldn't use it. All of the windshield repair kits out there are just adhesive/glue that stops the crack from spreading. You will still have the ugly crack left after the repair is done. Where is the crack at on the windshield? If it is in front of the driverside, it would be illegal to repair it.
I am not sure about the Permatex brand, but I recently used "Fix A Windshield" (same company as "Fix A Flat") and would recommend it. My crack (thanks to a stupid truck) was spider shaped and no bigger than a dime. Following the directions, it sealed the hole and made 99 percent of the crack lines disappear.