I am currently re-reading all the books from scratch, so I'll update this post along the way.
21. The Cigars of the Pharaoh (#4) (great story!)
22. Tintin in the Congo (#2) (controversial and no story)
23. Tintin in the Land of the Soviets (#1) (too much gags, no story)
24. Tintin in America (#3) (boring and too cartoonish)