Orthodoxy has very little defined doctrine. What little of it that it has is true; it's our doctrine too. (Not to be confused with erroneous Orthodox opinions, of which there are plenty.) But aside from that, underneath the traditional liturgy, valid orders, and folk religion (all of which are Catholic), theologically there's not much there. Like I've said, leaving Catholicism for it is intellectually like if Newman left for the Salvation Army (nice people, strong Christians: an offshoot of Methodism, yet another try at winning modern Britain back for Christ, but it's not the church) or Chesterton for the Jehovah's Witnesses.
Reminds me of people converting to Mormonism: nobody does it for the theology, because there is none worth believing in. They do it, and generations stay in Mormonism, for the culture. The theology's science fiction (and polytheistic, among other problems, such as an eternal universe and God as a created being: it's not Christian) but the culture, as Jeff Culbreath says, elevates natural goodness to a religion. They adopted the old America's wholesome cultural ideal in order to blend in (they're actually radical, not conservative) and are made fun of now for still having it. So somebody meets nice Mormons, wants what they seem to have, and joins. There are no intellectual conversions to Mormonism, because there's nothing intellectually worth taking seriously in it. (No St. Thomas Aquinas' five proofs, no Summa. Just Joseph Smith's and Brigham Young's imaginations.)
A lot of convertodox (self-hating Westerners like Rachel Doležal's a self-hating white) are that for the same reason: Byzantium's cultures are great. (We have them; we don't idolize them.) They want wholesomeness so they dress up like they think 19th-century Russia was like, for example. And, to give our secular liberal enemies in the culture war some credit: just like the evangelical or fundamentalist (actually different brands) worlds many of the convertodox come from, it can be pride that goeth before a fall, lying to themselves about their own problems (like the Duggars, now laughingstocks). A cult.
By the way, I don't think of myself primarily as an ex-Orthodox. An ex-Anglican, sure. (I've been in St. Margaret Clitherow's house, among other such places in England. I would never revert. The Anglo-Catholics I hung out with 10 years ago didn't believe in Anglicanism.) My faith (not that I'm holy) is entirely Catholic; my idiom (including the liturgical English, the first such I learned) for that faith is that of American Anglo-Catholicism from around the '50s, which, because it largely imitated Tridentine Catholicism (the theology was a little different: Hooker minus the Erastianism; non-papal), fits into it perfectly. (British A-Cism was would-be Roman Catholic and went Novus Ordo.)