This was not an easy book to read, but having got the bit between my teeth, I am very glad that I did so. On the basis of a first careful reading, my conclusion is that David Robertson did actually read the same book, whereas Mr Van Berg appears to have been reading something else - or perhaps skipped to the bits he wanted to disagree with. Plantinga is, for instance, quite careful to define what he means by 'random' when he describes natural selection, and he frequently cites key evolutionary scientists when he does so.
Having dabbled a little in the past with Plantinga's writings, and found them pretty challenging, I did find that the approach he has adopted here was extremely helpful. The inclusion of more technical material, more apposite for those with some background in the discipline of philosophy, but identified by means of a distinct typeface, was very helpful. This enabled me to make decisions about whether I should skip material or not (actually, 'not' became more frequent as one worked through the book) - and reinforced the fact that the book is appropriate for both novices and the more capable.
Plantinga's style of writing does encourage engagement with his subject, and he systematically advances his case (that theism and science are not in conflict, but that theism and science ARE in conflict with naturalism) by steady increments. His examination of the somewhat tenuous arguments employed by Messrs Dawkins and Dennett was particularly helpful - mainly because Plantinga's analysis helps to bring clarity to help one to see through the kinds of crassly dogmatic claims advanced by such individuals in pursuit of an anti-theistic worldview.
This kind of steady, systematic building of a case is very much Plantinga's hallmark. I can now understand that readers who jump in with 'Warranted Christian Belief' would struggle with it, given all the foundational work that he had constructed in the previous two volumes. This (for Plantinga) relatively brief work shows the care and rigour which he brings to his subject - unlike Dennett and Dawkins, and their acolytes, he takes great care to ensure that the groundwork is in place before he starts to build the upper stories of his case.
Another strength with this book is its structure. The 'Contents' section shows an utterly methodical breakdown of sections and subsections - and in the preface, he takes care to outline what it is that he is going to show his reader. I would like to think that this level of rigour would appeal to theists and atheists alike, and would hope that we would not see too much of the ritual shooting down of the great man - but I'm not going to hold my breath!
I would recommend this to any Christian wishing to work through issues relating to the interaction between 'faith' and 'science'. You will find that Plantinga's clarity and rigour will help clear many of the red-herrings out of the way, and reduce the arguments to their key components. An enlightening exercise, where so much else that goes on is an exercise in refined obfuscation!