Erudite != accurate.
Van Daniken or Velikovsky can appear erudite, after all. Or if physics is more to your taste, Wolfram's (he of Mathematica fame) great opus _A New Kind of Science_ is the huge, detailed, and researched work of a crank.
I've said that I admire Pagels' work, and I still do. I think her analysis and explication of Gnostic texts in works like Adam & Eve & the Serpent and the Gnostic Gospels is well worth reading, as is Beyond Belief. What I question somewhat is her characterization of the development of early Christianity, and the importance she ascribes to some of these texts in that historical process. I think her grasp of theological issues is sound, but I'm not sure her presentation of their relative importance is necessarily accurate. The Arian controversy, it seems to me, occupied far more attention in the 4th Century than spurious gospels, but spurious gospels were a pressing concern in the 2nd Century.