Richard Hopkins and I had some personal correspondence in the past, and he was the first person to invite me onto a radio show (his own, in Salt Lake City). To that extent I can affirm that he seems to be a gracious and honest person.
That's good news. Now on to the bad news: Although Hopkins is a nice fellow, very intelligent (an attorney by trade) and relatively high in the LDS hierarchy (his position might be roughly equivalent to an associational leader), Biblical Mormonism is, to put it mildly, not a particularly convincing piece of work -- at least not to an educated Christian.
The layman might find some aspects of it troubling, but once you realize that Hopkins isn't interacting with Christian material above the popular level (McDowell, MacArthur, etc.), it becomes rather less than impressive. Do serious research on the subjects involved, and it becomes clear that he is not that well informed.
My own book, The Mormon Defenders, addresses the arguments in Hopkins in depth, so I will leave it at this: I recommend Hopkins' effort for any Christian wishing to engage LDS arguments seriously. Although inevitably missing the mark, it is complete and comprehensive in its intent to present a case for a "Biblical Mormonism".