"Awesome classic"
This is standard Heinlein but that means top drawer Science Fiction. The racism topic may seem a bit old or corny but Heinlein is so good at making interesting stories that at their core are just morality parables.
"Not as good as the Mote in God's Eye."
The story is a bit slow and seems especially drawn out at the end. The characters are not particularly well developed except for the main 2 or 3. Several of the situations that caused major plot events seemed implausible. If you liked, The Mote in God's Eye, this one falls well short of the mark set by the classic.
"Famous and weak"
I prefer my protagonists to be more mature and heroic. Robin Broadhead is a childish loser whom I don't want much to succeed at his endeavors. Development of the main characters is poor. They don't seem to talk to each other much since they are so busy drinking, using drugs and having sex. The only real insight we get into Robin's character is from his artificially intelligent computer psychiatrist. And this insight is only in retrospect after the events of the book.
The basic premise of the story is that humanity discovers around 1000 alien space ships that we don't know how to use properly. This is acceptable. What is not reasonable is that governments or corporations would entrust a bunch of incompetent, loser, rejects with 3 weeks of training to take these ships out. I believe the military would be flying these ships. If not, why not use highly trained and psychologically stable civilians I was not able to suspend my disbelieve regarding this basic premise.
Maybe.
I liked the AI psychiatrist character.
I don't understand how this famous Hugo awarded book is liked by so many when it seems so weak to me.