Counterpoint: I've re-read it every five years or so since I was about 22, when I first read it (actually, I'd read some of the first one when I was much younger, maybe 6th grade, and got overwhelmed with the span of time and number of characters, but never finished it until I was about 22). I've loved it every time, and I'm just about due for another re-read and I'm looking forward to it.
There are some weaknesses, sure. Asimov himself was even aware of some of his weaknesses as a writer and talked about them occasionally in his memoirs and such. But, aside from HHGTTG and Dune, I can't think of anything that I've re-read more often, or that has been a more satisfying part of my reading life (and I read a lot). Asimov remains my favorite author after all these years. Admittedly, some of that is the "old friend" factor. But, nonetheless, I believe it is very solid sci-fi, and recommend it to anyone who hasn't read it.
I was really into it as a young teenager as well, but when I tried reading it a few years ago or so I couldn't get more than a hundred pages. I had the same experience with Catch 22.
I don't know what changed - it's a shame, since I was really looking forward to it. It's possible I'll give it another shot in a few years.
Poor writing was my first and foremost gripe: obvious character motives and an almost total lack of surprising plot twists. To be fair, I also re-read The Star Diaries which I first read (and loved!) in my early teens and I had the same issues with the author's workshop. That being said I think Asimov's prose hasn't aged very well in the light of actual technological progress (information storage and retrieval) and you just keep smiling while reading about Encyclopedia Galactica.
I read it as an adult and was disappointed by the flatness of the characters and the almost-total absence of any female characters.
To clarify: I'm not saying that people should shoehorn women into stories to satisfy a quota, I'm saying that stories that include women are simply more interesting, because they display a wider range of humanity and of the human experience.
Or, to put it another way, it's just boring to read a story where all the characters fit within a very narrow range of personality.
Sure, but 2500 years passed since and you'd expect writing to get a bit better. And yet Homer's characters are way more nuanced than Asimov's. Also, in Plato's Dialogs characters are completely irrelevant and are merely instruments that directly represent philosophical standpoints.
