All offer something unique imo.
I can't speak for Michael, but I have visited many of these National parks and although you could draw comparisions, each and every one has been an individual experience for me and it would be all but impossible for me to put them in order of preference.
I would consider paying that bit extra and stay in the National parks, if that's where you are planning on focusing your time. It can be quite a drive in and out of some of the parks [Arches and Canyonlands in particular] which takes up time and money in gas. Devils Garden campground is in a wonderful location in Arches NP and there are some good hiking trails that start from there. The Watchman campground at Zion is also nice and only a short walk to the shuttle buses that go into the main canyon area, so you can leave the car where it is and enjoy just 'being there'.