Guess it all depends on what you love in sightseeing. The South Rim is the tourist attraction. Lots of well marked viewing areas, walking paths, rest areas. If you basecamp in Williams you will be about 1hr easy drive from the park entrance. From the basecamp you can visit Flagstaff, Sedonna, Sunset Crater, and the historic town of Williams. We stay at the Williams KOA Circle of Pines. Since we are not really into hiking anymore, and at the elevation of the Grand Canyon even walking is strenuous, We prefer the South Rim. One of my kids and family who love hiking the back trails and wilderness enjoy the North Rim. I have no personal experience there.
Enjoy.