Back in the day, Robert Heinlein was considered "The Dean of Science Fiction." He and Asimov and Clarke were The Big Three of SF - at least in the English language - and Heinlein was considered the best of the best. Even Asimov and Clarke praised him as being better than him.
And he was. Better than them, I mean. You have to understand that while I respect Asimov a lot, he seemed to go out of his way to make his stories passionless a lot of the time (By his own admission) and honestly I never felt Clarke could write for sour apples. Put those two together, and it's like reading an instruction manual for how to eat crackers. Terrible. Heinlein at least seemed to understand that stories need a point, people, and a beginning, middle, and end. That's something that escaped a surprising number of Golden Age SF writers, particularly of the "Hard SF" variety.
Thing is, while he was better than those two ambulatory sleeping pills, he wasn't neccisarily a great writer. "I don't have to be able to outrun the bear, I just have to be able to outrun you." There were a bunch of others in the genre who were honestly a lot better. Ray Bradbury is unquestionably the best of the camp. Stanley G. Weinbaum, while not the most ellegant of authors is arguably more fun than all of the big three combined. Philip K. Dick and Harlan Ellison turn up at the end of the Golden Age, and they're both better. Lewis Padgett was hilarious. Thing is, all these guys are "Soft" SF writers. They're not engineers and they're generally not interested in the hard science aspect of SF, except as a means to an end. But if you want hard SF, ok, George O. Smith, who's not the greatest of writers, but he's no worse than Heinlein. He's got such an infectious can-do attitude and American Optomism, and he's lacking Heinlein's Mary Sue and "Everyone's an idiot but me" attitudes that I rank him higher, on average.
By the 1960s and the New Wave of SF, you had JG Ballard (NO ONE could set a mood like him, even though his later work is repuslive and sick) Ellison and Dick were able to excell in the New Wave days, and while Bradbury was never a New Wave writer, his increasingly-impressionistic style was good enough that the trends of the day didn't matter. People continued to read him.
Heinlein? Not so much. If you look at his books from this period - including some that are regarded as classics - they're actually borderline-unreadable. The Moon Is A Harsh Mistress is 1/3rd of a really good novel attached to 2/3rds of the second-most-boring political screed of all time. "Starship Troopers" actually IS unreadable (I reviewed it on the site), so I'll say no more about it. From there out, it's onward and downward as ol' Nazi Bob the Wonder Fascist becomes increasingly obsessed with incest, creepy swinging, and retroactively trashing characters from his classic stories ("Hey, let's go get the gang from that book there, and invite 'em to the orgy!" "That'll be cool! The women can talk about penises in an unrealistic fashion!" "Neato!")
I will cut him some slack: He had a good run. From about 1948 to about 1960, he was the undisputed king of the Juvies, and a lot of those books are a lot of fun. Anything on either side of that, though - ugh - garbage. I will cut him some more slack: he evidently suffered a major brain injury about 15 years before he died, which undoubtedly adversely affected his gifts. Still, "Not knowing when to quit" is no excuse, right?
So: do you guys love, hate, or 'meh' on Heinlein?
Myself, I kinda' hate him.