I guess as many have stated depends on what you like. If you are just passing through looking at the scenery through the window of your vehicle they are quite nice. If you like to hike they are great.
Canyonlands NP actually has three districts- Island in the Sky, Needles and the Maze. The first two are on the east side of the Colorado River and the Maze is on the west side.
Island in the Sky for me is my least favorite of the three but still very well worth seeing and exploring with a definite stop at Dead Horse Point State Park. Driving the Schaefer trail (not in a motor home or car) is a very nice ride, yes it is off road but I have seen cars on it and could be done but a bit of clearance would be best wont need 4wd.
Needles is really where the hiking and wheeling action comes in though in addition to some great scenery. Head over to Elephant Hill and wheel (where you will need 4wd, high clearance etc if you go onward past the parking lot) or park and hike the trail(not the 4x4 road) to Chesler Park or beyond. You can spend a few days hiking the area or choose to go as far as you want. Even .25 mile down the trail you will see stuff you wont see from the road and is quite worth even just doing a short distance.
The Maze District takes the hiking and wheeling to a whole new level. It is very remote. Some of the wheeling trails are quite tame and most any 4wd high clearance vehicle can do them. However once you get to the Flint trail you will need to be prepared for more intensity. Going down the initial hill of the Flint Trail is a bit tough but I have done it in a full size pickup. Once to the bottom it is not bad but it is lengthy to get out the other end as you will come out down by Hite on HWY 95. If you really want to get in more wheeling once down the Flint trail head up Elaterite Basin and into Earnies Country and on up to the Doll House that trail splits off the Flint Trail down by I think it is Waterhole Flats. This is a tough road high clearance short wheel base will be your friend. I tried taking my truck up there but decided body damage was not on the menu that day after a few miles. It is not all hardcore but there are certainly stretches that are quite rough on that part of the trail. The hiking in the Maze is very good but you must be prepared, it is very remote and very few people. You need to be prepared to deal with obstacles like pouroffs, moki steps etc. Best to bring along a length of webbing or rope to help in certain cases. We hiked down in to see the Chocolate Drops and other things one day and as we got down to the bottom of a canyon we say a guy walking towards us looking a bit worn and bedraggled. Turns out it was a ranger. He was heading out he had been out a week and his job was to check permits etc his week tour was up and once he got back another ranger would head out for the same. It is something like only 1% of the visitors that go to Canyonlands go to the Maze. It is awesome but it is fairly hardcore.
There is another part of the Maze area called the Horseshoe Canyon Unit. It is not really part of the Maze but is right there. It has one of the finest examples of archaic rock art in the world, not just Utah or North America. The Great Gallery as it is called is just an incredible panel of rock art. Life size drawings and larger and over 200 feet long. There are also many other lesser panels along the trail. Getting to it is not hard and the trail is not bad about 6 miles round trip iirc with a 600ish foot drop down into the canyon, then the trail just goes up canyon not hard. However don't go without water as there is none there. If you are capable of it do it you will not be disappointed.
Capital Reef is nothing much if you just pass through on the HWY 24 beautiful yes but you miss so much if you don't get off the highway. Aside from the hikes and viewpoints right off 24 and the other main road road heading to Grand Wash there are few other roads. Hartnet Road and Cathedral Valley while not hardcore wheeling no cars are going to make it. And you have the Notom Road which skirts the Eastern Boundary of the park for a while then is all within the park and follows the Waterpocket Fold south to Lake Powell. It gives you access to the Burr Trail along with a few hikes that enter the Fold. The Notom road and the Burr trail while not suitable for a motorhome or trailer could be driven with a car. A great loop drive is go down the Notom Road to the Burr trail then up once on top of the Burr trail the road is paved. The scenery is fantastic and will dump you out in Boulder Utah on HWY 12. At which point you can take 12 up and over Boulder mountain with it's great scenery back down into Torrey on the west side of the park.
If you don't like "eyeball bustin" scenery I wouldn't go to those places. If you don't like hiking I would still go. If you like hiking and great scenery you will be in hog heaven as each of those areas can offer more than you will have time to get done.
2016 Jayco 28.5 RLTS