^^^Charles Manson disapproves.
Stranger in a Strange Land is a lot livelier than something like Time Enough for Love or I Will Fear No Evil or even Number of the Beast. But in the end it's all about imagining yourself with superpowers because you're so much better than other people. It's quite a mind-blowing experience if you're thirteen years old (as I was when it read it,) particularly if you come from a strongly evangelical home.
As an adult? Don't see how it could be worth much. Despite my sentimental regard for childhood reading of other Heinlein books, I can't say the world would have lost much if everything after The Moon is a Harsh Mistress had been lost. I've learned how derivative of Twain, Mencken, London, Shaw Heinlein's style was, but when it's your first exposure, it was enthralling.