Had been by briefly a couple of times many years ago, then about 2 years (in Sept 2018) ago my wife and I spent almost a full day (sunrise to about 3:30pm) moving to various locations along the south rim – it was well worth the time.
Never been to the Southern Rim but have been to the Western GC a couple times. First, about a month after the Skywalk first opened in 2007. They hadn’t even paved the road yet - it was just rough-graded, with scattered chunks of dirt and rocks that you had to avoid.
The second time, we took a helicopter tour from Vegas - over the Hoover Dam and Lake Meade. We landed in the Western Grand Canyon along the Colorado river, where we ate a picnic lunch before flying back.