This is an interesting and very well argued effort to produce a plausible modern version of perfectionist moral philosophy. Hurka draws on a very rich prior perfectionist tradition that goes back to Aristotle and that Hurka argues includes an impressive variety of contributors including Aquinas, Marx, and even Kant. Hurka, however, dispenses with some of the historic justifications for perfectionism including Aristotle's teleology and Aquinas' dependence on theism. What follows is a form of Aristotelian perfectionism based on the basic intuition that the good is the development of the essential distinctive feature of human nature, rationality. From this plausible foundation, Hurka systematically develops a form of perfectionism which emphasizes development of human capacity with a strong consequentialist orientation. Hurka's development is quite impressive, leading to a form of perfectionism that is relatively liberal and egalitarian, as he says quite compatible or even favoring a mixed economy or social democratic state. He also discusses other versions of perfectionism, such as Nietzschean-like versions which he terms maximax versions in which perfectionism aims at cultivating the perfection of an elite few.
Hurka is quite frank about some of the limitations of perfectionist approaches. In this case, perfectionism is constrained by appeal to reasonable moral intuitions but without such constraints, very different and less attractive alternatives are plausible. Perfectionist approaches may not necessarily to lead to endorsement of common moral values, can lead to destructive elitism, and in some interpretations, denies the existence of rights. While Hurka's perfectionism is attractive, his discussion of limitations of the general approach points out what may be a major weakness of Hurka's approach. Hurka's perfectionism is plausible only by appeal to certain moral intuitions. But how firmly grounded are these intuitions? There is a relatively popular version of perfectionism that has little in common with Hurka's thoughtful program - Ayn Rand's Objectivism. This fervently elitist faux-Nietzchean ideology has a quite a few followers, some of them quite influential. Since few of Rand's followers have subjected Rand's books to the careful level of analysis used by Hurka, it must have considerable intuitive appeal.