As of this minute, I just finished reading James McGrath's book, The Only True God: Early Christian Monotheism in its Jewish Context. I need a bit of time to gather my thoughts, but expect a review (probably in a series) soon intermixed with ongoing discussions of Bauckham's Jesus and the God of Israel, which discusses much of the same issues with different results.
I will give a few general impressions. James's book is very succinct and perspicacious--a wise man once said, "Brevity is the soul of wit." He directs his book towards non-specialists, so he takes time to explain a great deal that scholars' assume, but I think this is an important exercise for all scholars, since we often forget why we assume what we assume and what we assume as a scholarly community needs continual reassessing. It is quite amazing that even explaining these issues, he gets in detailed exegeses of passages and reviews of entire corpi of literature and even material evidence in such few pages.
If I would sum up in one (long) line the difference between McGrath and Bauckham, it is that Bauckham sees similarities between Jewish and Christian monotheism (by the way, they both accept the term, both recognize it is anachronistic, and both note that modern definitions differ from ancient conceptions) in terms of the inclusion of Jesus within the divine identity (in terms of enthronement, sovereignty, and worship), whereas McGrath, while recognizing that theological perspectives are living things that grow and change over time, sees continuity in Jewish and NT views of God with Jesus as a highly exalted agent of God who, like Yahoel, etc., shares God's name ("LORD"), is enthroned (much like other figures), is an agent of creation (like Philo's Logos), but who only receives προσκύνησις(a rather generic term that can mean anything from a "bow" to "reverence" to full-scale sacrificial worship) and, unlike the "one true God," never receives cultic, sacrificial worship--what McGrath sees as the true worship dividing line between Jews (and early Christians) and non-Jews. It is precisely in the highly exalted mediator (agent) figures that Bauckham rejects that McGrath sees the true continuity between late Second Temple and NT theology.
I will let James assess whether my general impression of his book is accurate. For more detailed discussions, wait for later posts!