A very interesting post at Mormon Matters, reviewing a 1989 book titled "Will the Real Heretics Please Stand Up?" The book was written by an attorney who grew up a Jehovah's Witness, then became an Evangelical Christian. That lasted until he conducted a thorough reading the original writings of the pre-Nicene Church Fathers.
The author discovered a variety of doctrines embraced by early Christians but repudiated by the post-Nicene Church. This led to the author's disenchantment with modern Evangelical churches. He wandered a bit, then finally affiliated with the Mennonites, who trace their roots to the Anabaptist movement, sometimes termed the radical branch of the Reformation. That was the best match the author could find to his own laundry list of early Christian doctrines.
The post makes some quick comparisons between the author's list of early Christian doctrines, LDS doctrine, doctrines of 19th-century Restorationist sects, and the Mennonites. For Mormon readers, the post should make them read more carefully when LDS histories cover the 1830 conversion of Sidney Rigdon to the LDS Church. Rigdon was a minister in the Restorationist Campellite movement who brought many members of his congregation into the LDS Church with him. He quickly became a close confidant of Joseph Smith and was eventually made a member of the LDS First Presidency.
For Evangelical readers, the post and the book suggest a bit of caution when applying the label "heretic" on the basis of doctrinal disagreement.
It's worth noting as well that the author was an attorney by training, not a scholar of early Christianity or ancient languages. So the book (which is only 190 pages) appears to be more of a general treatment of the topic, not a scholarly treatise. And I'm not suggesting readers go join the nearest Mennonite congregation after reading the post or the book. Not that there's anything wrong with that.
Originally posted with comments at Beliefnet.