I think my wife is more qualified to speak about his writings. He has been more of an influence on the writers I read during my bigger Sci-Fi period in high school. Heinlein definitely left a mark in the character or tone of the RPG Traveller, for better and for worse.
Most people will always tie his name to the movie version of his novel Starship Troopers. I readily admit to not reading the book (it’s way down my list of things to do) but I know Paul Verhoeven’s film only retained a few elements: names, a war, the Arachnids. Despite the “innaccuracies,” it’s still a great movie which has sadly predicted the parody-mess we live in today. Just insert the Middle East for Klendathu.
As for Heinlein’s politics, life, etc. Who really knows because he’s been dead for 19 years and when he was alive, he seemed to be rather evasive and a series of contradictions. He was a normal person, just more famous and successful in writing novels. He also gave us the word grok that was recently used in an interview with Brad Bird. I did look it up at webster.com (it won’t link) to confirm this, it’s there but not in askoxford.com.
I first read A Stranger in a Strange Land because I was told it was one of the best science-fiction books ever written. In all honesty, I thought the story was fairly weak and that all the excitement was due to his espousement of “free love”. Fortunately, I was willing to give Heinlein a second chance because many of his other stories were brilliant. OK, maybe not brilliant, but they were interesting, compelling, and quite a few had strong female protagonists (something that wasn’t very common at the time). Of all his books, I love his juvenile fiction the best, and still have copies of Red Planet, Starman Jones, Have Spacesuit–Will Travel, and Between Planets. I think my oldest nephew is almost the age where he’ll appreciated them as much as I do.