Edited to add: I realize post-juvenile Heinlein is not to everyone’s taste — and I’m personally convinced Double Star may be his finest single book — but if one is interested — Stranger, Glory Road, Starship Troopers, Moon is a Harsh Mistress, are all worthwhile — and different from each other.
I’m not gonna defend Farnham’s Freehold, but each of the other later Heinlein works not listed above has some merit, though mostly for real fans only.