I recently finished reading John Frame's book, Cornelius Van Til: An Analysis of His Thought. While I have read almost all of Gordon Clark's books, I have never sat down to read an entire volume of Van Til. The most exposure to Van Til that I've had is reading about half of Bahnsen's Van Til's Apologetic, which casts its focus more narrowly than Frame's book, but has the benefit of extensive quotations and readings from Van Til's works. Given my limited exposure to Van Til's thought, my comments here will be of a general character.
Frame's book is organized as follows: Part I, which includes three chapters (a general introduction, a biographical chapter, and a brief statement on his legacy); Part II, which examines Van Til's "Metaphysics of Knowledge" in eleven chapters (three on God's nature, two on knowledge [one of which is about the Clark-Van Til controversy]; and one each on Scripture, Presuppositions, Primacy of the Intellect, Logic, Analogical System, and Evidence); Part III, which looks at Antithesis, Common Grace, and Rationalism/Irrationalism dialectic in three chapters, respectively; Part IV, which analyzes Van Til's criticisms of traditional and contemporary apologetic methods as well as expositing Van Til's own method, with an example of it in practice (a total of seven chapters); Part V, three chapters on Van Til's criticisms of philosophical and theological positions past and present; Part VI, two concluding chapters; and two Appendixes, which include a criticism of "Ligonier Apologetic" by Frame and an essay on Van Til's preaching by Edmund Clowney.
Despite the wealth of information included in the volume, it is a fairly easy read for a philosophically oriented book. Frame has a congenial tone to his writing and his criticisms are predominantly focused upon providing the best possible reading of the individuals and seeking the clearest possible terms for engagement. If there is a general weakness, it is probably that Frame's desire to incorporate the best reading leads him to overlook the seriousness of some of the logical implications that will be commonly drawn from the confusing language that he finds in various authors.
The best part of Frame's book is his familiarity with Van Til and his comprehensive treatment of the various topics of Van Til's thought. Frame is not as acute as Bahnsen in his analysis, but Bahnsen's book is less comprehensive, and I think more biased in its analysis of Van Til's opponents; and especially of Gordon Clark. Frame actually gives a lot of ground to Clark in the controversy, but not enough to really bring out anything insightful into the ongoing issues between Clarkians and Van Tillians. Another strength of the book is Frame's appreciation for the effects of a "movement mentality" that arises around strong personalities such as Van Til. Even if Frame were exaggerating the effects of the movement mentality upon Van Til or his followers (and I have no reasons to suspect such exaggeration) it would still prove a sound warning for anyone investing their energy in so-called intellectual giants of a given time. I have sensed my own desire to defend my intellectual heroes beyond reasonable limits, in part because being found in error has less to do with the "glory" of the individual hero and more to do with the sense of loss on one's own investment in their program of thought. Of course, there is no real loss in discovering errors in any thought, since a discovery of error is a step toward truth--but psychologically, for those like me anyway, the first response to such errors isn't joy.
To speak more specifically about Van Til, the most intriguing aspect of his thought seems to be his ability to penetrate to the fundamental problems of a given philosophy or theological system. This certainly made Van Til unpopular with his contemporaries, since (think of the movement mentality again) few people respond well to having their poster-boy's philosophy deflated upon one or two points of critique, as opposed to the sort of nuance and caution that academics tend to employ in evaluating major players. Van Til's rejection of Barth is notable on this score, but also his ability to see that all forms of pagan philosophy necessarily presuppose truths derivable only from the God of Christianity. Admittedly, the sort of criticism lends itself to overstatement, since discerning logical presuppositions and/or implications are distinct from discerning the stated beliefs or entailments of a position. That is to say, all of us possess inconsistencies in our thought, which lead us to believe things about our position that contradict other aspects of which we are unaware. The incompatibilities of our own position are by definition "off the radar" until they are pointed out to us, and the most natural response is to defend our position until such inconsistencies have been fully demonstrated as valid and sound. Then, of course, there is the additional problem of unbelief, which is that unbelievers by nature have a true sense of God's existence and divine authority (Romans 1), but flee from it with all of their might unless God arrests their rebellion through His regenerative work.
Although it would be natural to go from here into the implications of Van Til's strongest contribution, I will leave it to my readers to investigate for themselves Frame's helpful book and Van Til's own writings. I would recommend Bahnsen's volume rather than a smattering of Van Til's own works. Bahnsen is far clearer than Van Til in his exposition of Van Til's own philosophy, if only for his more careful attention to the meanings of terms and his attention to translate technical terms into explicit statements or propositions.