We had a fantastic experience with Navtec on the White Rim Trail.
We are a family of 4 with two teenage sons. We've been to a lot of National parks - and definitely seek out the experiences that get us the deepest into the park that we can go.
Canyonlands is vast, and driving around on the mesa in Islands in the Sky isn't going to get you very far or really experience what the park is. We considered renting a Jeep from one of the many vendors in Moab, but knew that we wouldn't necessarily maximize the time we had without prior knowledge of the canyons or the mesa, as well as the risk involved with driving an unfamiliar vehicle.
We settled on Navtec's tour, and we got a great tour. We were able to visit several of the canyons, seeing washes and scenery that is impossible to see without getting offroad.
Our guide was knowledgeable, friendly and hospitable, and just enjoyable to spend the day hanging out with. Navtec's Land Cruisers are comfortable, and had adequate space for our family and our gear for the day.