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Sorry, I haven't read that book. Otoh I have enjoyed several scholarly articles by Ehrman in his particular field, i.e. textual criticism, before he became famous. Textual criticism is a very technical and obscure discipline, generally unknown from the large public, so its popularisation is something of a challenge: it's difficult for a textual critic, who is usually concerned with tracing variant readings on minute details of the texts, to say something "big" by mediatic standards without overstepping the boundaries of his/her area of expertise. But from the discussions and recommendations here I understand it must be pretty good for its kind, and I have no doubt about Ehrman's scholarship and honesty.
Something I have learnt from textual critics (perhaps more in the OT field, like Emmanuel Tov or Dominique Barthélemy) is the enlightening lesson of a frustration: Bible scholars, translators, and readers at large resort to textual criticism as a tool to reach for "the original text". What you find instead is that there is no such thing, because there is no clear-cut border between textual and literary criticism. Every manuscript, every "family" of manuscripts, is worth to be studied for itself and as a part of a multiple textual evolution. It is almost impossible to decide, for instance, between the Alexandrine and "Western" traditions (which differ widely in parts like the book of Acts), which bests reflects an "original". The two developed simultaneously, sometimes separately, sometimes influencing or reacting to each other, always following their own "logic" which we miss as long as we're after "the original" and dismiss what looks "secondary" as mere (i.e. worthless) variants.