I read this the other day and was disappointed. I suspect the real reason Heinlein never finished it is that it was too trite and too much of it is silly. He relied heavily on ideas he lifted from previous work and from other classical authors. The dialogue is not his best. The ending is a straight lift from one of his other novels--I won't say which unless you insist.
I read it because of the author. With an intro by Weber, I expected that it would be a really knockout opus but it just isn't.
If you appreciate his work, don't spoil his image by reading this.