I doubt I'll read many more, but I have now bought and read Cigars of the Pharaoh, which is next in date after the three you mention, and which was a childhood favourite. It turned out to be fine, though I wish it had developed its plot more deeply in fewer places rather than rushing around everywhere.If you're going to read them all I would skip the first three: Tintin in the Land of the Soviets, Tintin in the Congo, and Tintin in America.
One slightly mad thing is that Tintin is recognised by an Arab sheikh from his published adventures, and is shown the cover of Destination Moon, despite that being written in the 1950s and Cigars being written (and clearly set) pre-war. It seems Cigars was only colourised after DM was released, and they changed the art then. I wonder what it showed before?