I originally booked this tour as a way to break up a long trip of hiking, hiking, hiking in 4 different national parks. What I didn't realize is that the benefit of this tour was less about adding a little variety to our trip and more about getting a completely different perspective on the national park.
The half-day Canyonlands tour takes you on the ride of your lifetime down at the bottom of the canyon. Later, if you plan to hike the national park, you will see the same canyon (and the dirt roads you've already ridden on) from above. It's a completely different perspective and it completely changes your view of the park. This alone makes the trip worthwhile.
I want to mention that it was our tour-guide, Ben, who really made the trip special for us. Ben has been driving off-road for most of his life and has lived in Moab all of his life. He was kind enough to share a bit of his personal life story with us, the history of Moab (and what it was like to grow up there), and a tiny fraction of his wealth of knowledge about 4X4 driving and the uniqueness of the vehicles he operates. He was also there to repair, on the fly, one of the other vehicles that had broken down in 102-degree heat. We felt ourselves to be in more than capable hands. That made a HUGE difference in our enjoyment of our trip.
I don't know what competing companies offer, but I've been on enough tours of all different kinds to appreciate this about NAVTEC: it was professionally run (follow-up emails and reminder emails were sent, a "night before" phone call was placed to confirm, the tour departed on time). Ben made it clear to us that a high level of skill is demanded of drivers who work for this company and that the company maintains a high standard for maintenance of its vehicles.
The only minor criticism that I can make is that the tour guides are not trained to impart a specific body of knowledge to guests. I often felt they were winging it when it came to the prehistory or geology questions which naturally arose. To that end, Ben is attending college geology courses to self educate, so maybe future guests will get to avail themselves of his education. I, personally, wasn't on the trip for a lecture, so this didn't bother me at all.
My only regret is that I didn't book a second tour during our stay. I think the Needles trip sounded thrilling.
(P.S. Ben -- we're rooting for you and hope you win your bid for the Lexus!)