A lot of people in my social circle tend to go on about how great Robert A. Heinlein's Stranger in a Strange Land
is and how reading it was a life-changing event for them. Quite honestly, my own reaction to it was rather meh. I read it as a senior in high school, and I remember finding a great deal of it tedious. Even if I hadn't borrowed it from the library, I really wouldn't have felt much desire to re-read it. When I did acquire a copy of my own, it was almost as much for the sake of completeness of my personal library as anything, and I never did get around to re-reading it.
Instead, my life-changing reading experience happened two years earlier, when I acquired a copy of Frank Herbert's Dune. Reading it was such a consciousness-expanding experience for me that I often felt as though my brain were about to burst from all the new concepts I was discovering. I think I must have read it six or seven times in the first few months I had it. I know I read it so many times that it began to literally fall to pieces, and although I still have that original copy, it has been mended so many times it's held together by tape and must be handled very carefully.
The biggest problem for me was that Stranger in a Strange Land had a very unsteady tone. There were sections that I found quite interesting, and others that I found to be utter bloviating boredom. At the time I didn't have the literary expertise to understand why, but looking back on it, I can see how Heinlein wobbles back and forth between rigorous scientific extrapolation of what it would mean for a human child to be raised by Martians and searing social satire. The result is a very uneven book that ultimately bogs down in preaching to the point where it's uncertain whether he might actually be advocating some of the things his protagonist is putting forth.
By contrast, Dune maintains a solid tone throughout, with vivid worldbuilding that all fits together. Every element builds the experience, to the point that you almost feel like you're actually there. Furthermore, it rewards rereading -- when I go back to it for another reading, I frequently find details that I had previously missed, and which shed new light on the entire novel.
In fact, I would argue that Heinlein's actual masterwork, the novel which for him was on the level that Dune was for Frank Herbert, is in fact Starship Troopers. To understand this, you first need to completely forget about that awful movie that was made in the late 90's and concentrate solely upon the text of the book. In it he maintains a consistent tone and storyline to create an extended meditation on the nature and meaning of citizenship. In it, he brings together the themes of personal and civic responsibility that he had been developing throughout the juveniles and his various short stories. Everything afterwards was a downhill slide into oblivion.