This tour was the best highlight of my trip to Iceland. We had a small group of around 12-14 people on our mini-bus for the day. Our driver/guide was informative and engaging all day, and was an expert glacier guide. We walked past all the big-bus tour groups milling around at the bottom of the glacier, put on our crampons and helmets, and hiked away up the empty, quiet glacier. I got to see things that only a small fraction of tourists will get to see. The tour stops were timed so that we reached the glacier around noon, and we mostly had the glacier to ourselves for our hike, since other tours take people for lunch at that time. The hike is quite long, but only moderately strenuous, and we took lots of photo breaks on the way up. Anyone in good health should be able to do it.
We stopped to buy our lunches at a convenience store before the hike, and then ate on the bus after the hike, on our way to the other waterfalls and black sand beach, so no time was wasted. Everything was efficient, giving us plenty of time to see all the natural attractions at the stops. All the south coast tour buses stop at the same places, but the chance to hike on the glacier instead of simply seeing it sets this one apart.