I thoroughly enjoyed this book on reading it, although it starts a little slowly, different from much of his earlier work.
Lots of the stories stirred a lot of emotion for me; not an emotionally aware person when I first read it and as well as being fun and interesting to read about adventures; and the perspectives of Lazarus on life it broadened the way I thought about things a lot and asked many questions which are good questions to have asked of oneself.
Characters and lifestyles in this story are very 'earthy' and very much challenge the normal point of view one is raised with. But this is not a bad thing and it is not obvious that someday we may not evolve to have families of similar types that Heinlein depicted. However, such living is not something most people today could accept the idea of never mind the reality.
Philip K Dick certainly disliked the politics of Heinlein, but his books themselves were full of the surreal, revolutionary and often utterly bizarre and no less challenging then Heinlein. I suspect those who do not like this work worry as it is closer to reality and thus easier to identify with as an actual future which is objectionable to them.
It does ask the question of what is really natural behaviour for people and, if there were no taboos or economic restrictions how would people choose to live? How many children might they choose to have? What would one do if one could live, essentially indefinately?
Whatever challenging ideas the book has overall it is a work of beauty and strikes me mainly, in all of the strength that there is when a group of people love and help one another.
The idea that a person can love more than one other person is as true as anything said anywhere else. It has added richness to my life and I would recommend reading this book as thoroughly enjoyable and well worth reading.
And I never got my copy back when I lent it out!