The difficulty with most of these sites is not that they are criticizing Orthodox Christianity as it is but basing their critiques on misconceptions of Orthodox doctrine and practice. Sometimes elements of Orthodox teaching can be recognized, but the way they are put together is often quite bizarre. Irenaeus of Lyons wrote about how heretics took elements of the faith and rearranged them, so that what once was a mosaic of a king becomes an image of a dog (or something else).
One significant exception is Daniel Clendenin, whom many Orthodox Christians respect for being much more thorough in his research. In that, he is relatively unique among modern critics of Orthodoxy. His ultimate reason for rejecting Orthodoxy is spelled out in terms of his commitment to Protestant distinctives, a viewpoint which draws the lines clearly, rather than proceeding from the position that we all share the same basic assumptions and that one's interlocutor is drawing dishonest conclusions based on them.
Roman Catholic Polemics
- Orthodoxy and Catholicism: A Comparison - Dave Armstrong