I have the stick-on type myself. My reason for them was I painted them to match the truck. IMO they do blend in with the contour of the truck better than the window channel style, when painted JMO. I agree they are a pain if needed to be replaced, but there are ways to ease the pain some. You could use the fishing line trick to remove, and there are adhesive removers that work pretty good getting the junk off. Otherwise if I was not going to paint them I would have probably went with the window channel style.
Also it can be done on the replacing mirrors though, with the stick-on type visors. You have to be patient, and not get into a hurry like I did on the passenger side I did first, I did crack it (the window visor, that is) removing the standard mirror to replace with the new tow mirror. The drivers side went alot smoother though with no problems and damage. Still a slight pain to do. :-laf
Tony