How well do they work? Excellent. :) Except when you can't catch a signal due to trees and other obstructions. :(
If travelling the Oregon coast for example, that can be difficult due to all the trees. Some treed CGs will tell you what sites or sections are good for reception or you can look for other RV-ers that already have dishes set up. In some cases, you can use a really long coax cable and set up a dish farther away from your camper to find a hole between trees. If you just can't get a signal, there's always the chance of OTA or cable TV as a backup. Some cable TV providers have upgraded to digital which is pretty good (just had that on the OR coast).
You can use an app on your phone to find the satellite(s) in iffy locations. Can really help to use before backing into a site and discovering you can't watch TV. Dishpointer has a good one but there are others. For a dish on a tripod, you can also look up azimuth, skew and elevation on dishpointer.com or other websites
If you have sat TV at home, all you need to do is take an unused spare receiver from home for no extra costs. If you don't have sat TV at home now, it might be cheaper overall to convert to satellite TV at home, but need to see if your favorite channels are available from the sat. provider or if you need to upgrade to a more expensive bundle.