McLintock is a romantic comedy first, a western second. As a romantic comedy in an old west setting, it works quite well. This is John Wayne at his best, in my opinion. I haven't seen many of the "serious" westerns he made in his younger days, but I did see "True Grit" (the movie they gave him an oscar for). I thought it was awful. Of course, that wasn't necessarily Wayne's fault, but he looked as though it was all he could do to keep from bursting with laughter throughout most of it. Like a number of other macho actors (Burt Reynolds, for example), Wayne has a certain dry wit that comes across well. Here he is paired with Maureen O'Hara, and they make a good team. There are also lots of other familiar faces in this (Chill Wills, Stephanie Powers, Yvonne deCarlo, Jerry VanDyke, and more) who contribute solid performances.
McLintock isn't a great movie. It will not go down in the annals of film classics. Most of the humor isn't terribly original, and the fights in the mud pit are pure slapstick. Then again, there's nothing wrong with that. They work. It is an entertaining, funny movie and most folks will have a good time watching it. Give it a try. I give it a strong 4+ stars. Be careful what edition you get, though. I have no problem with mine (the John Wayne Estate authorized edition), but apparently some editions are of poor quality.