I went on a trip with Escape several years ago. We met in Las Vegas. They picked us up in a van with a tire that was low on air. We drove all the way to the north side of the Grand Canyon in a top heavy van full of people, loaded up with all our gear, bicycles, water, food, etc. We made it to the starting point and started riding. When we got to the campsite the van wasn't there. The tire had blown. If this had happened on the interstate we could have been killed. We sat around freezing while we waited for our gear. When the van finally arrived it was after dark and they offered to make us sandwiches instead of the planned feast for dinner. Most of the group said "O.K." but I said "no way, I want the good stuff". The others changed their minds. It was a bad start to the trip. The rest of the trip was fine and the riding along the North Rim was great.
Keep in mind that the trip was several years ago and the company was still called Escape the city Streets. It was bad judgment by one of the guides that could have gotten us killed.
I have been on many of these type of supported tours. They are great if you don't want to deal with support, cooking your dinner, cleaning up, planning your ride, permits, etc.
I have been with http://westernspirit.com/ 3 times and going on a 4th trip this summer (Umpqua River, Oregon). I can't say enough good things about this company and highly recommend them.