We (me, wife, 14yo son) did the South Kaibab Trail day hike through Wildland Trekking on Thanksgiving Day 2019, and had an absolutely outstanding experience!
It goes without saying (so why am I saying it?) that any first experience of the Grand Canyon will be amazing and overwhelming. If you've never been, we encourage you to go. Theodore Roosevelt was right when he said the Grand Canyon is "the one great sight which every American should see.”
However, rather than just going to the Park and using the maps to hike on our own we decided to take a guided hike, and we are so glad we did. Our Guide, Betsy H., was fan-bloody-tastic. She absolutely made an already wonderful place even more interesting - and safe! Everything about our interactions was top-notch. In the days before the hike she contacted us several times to make sure we were ready. The weather forecasts for the day were a bit sketchy, and we greatly appreciated that she was letting us know and making sure we were geared up. We also got the sense that as a true professional she was sizing up her clients in terms of our abilities and willingness to endure, which we did not mind at all! Similarly, on the day of the hike she let us know the planned turn around, but extended a bit when we made good time on the way out (and probably gauged our general fitness for the significantly more strenuous return up the trail!)
Betsy was the best combination of personable, easy-going, knowledgeable, professional, and a just plain wonderful person with whom to spend six hours. She knows a lot about a lot - indigenous people, geology, botany, weather, animals, survival, climate, mules trains, prepping a great lunch, ecology, and how to make suburban day hikers feel cool. My wife and I were also very pleased with the way she directly engaged with our 14yo son, and treated him like an interested party (which he was, to be sure, but sometimes the kids getting overlooked). Even more impressively, she provides this same broad guided experience around the world (Patagonia and Mount Kilamanjaro are the places I recall)! Although the weather cooperated that day, I have to say I'd have felt in excellent hands if it had quickly gone south.
All of the above and more is what made the guided experience so much better than us doing it ourselves, and so very well worth it.