My car's front lip has two long scrapes which caused by the previous owner . They are about 4-5 inches long.

Have anyone here use scratch wizard's kit before? Do they do a good job matching the color? I have GPW

Is it worth the time to sand them down and repaint it myself or just get the brush type and paint it over?

 

Depends how much you're willing to spend really. I would get myself a couple cans of colour matched spray paint if you don't have access to any proper painting equipment.