But it's mostly surface stuff. All Episcopalians use the same prayer book (although you'll find that "high" churches tend to use Rite I and "low" churches Rite II). The only serious doctrinal point that I can find any disagreement on is the Real Presence. High says yes, Low says no.
The XXXIX Articles at this point are more of a historical curiosity than anything else. They are highly colored by the politics of the reign of Elizabeth I . . . and they were removed from the latest revision of the prayer book as a statement of belief - they are now styled a "historical document".
This was necessary because of some of the frankly anti-Catholic language contained therein . . . the first time we went to church as a married couple (a LONG time ago!), we wound up at an ultramontane church in Atlanta - perhaps "the" ultramontane church in the metro area - and my husband kept asking me during the service "do you believe in [incense, the Rosary, etc.]" I would respond, "Some of us do, some of us don't. It's o.k." Then Fr. Roy Pettway (now retired and may no longer be with us - this was over 25 years ago) climbed into the pulpit and preached on Purgatory (on Easter, yet!) Hubby asked, "Do you believe in that?" I replied that I didn't think so and flipped to the XXXIX articles - which denounce it as a "vain and Popish doctrine, fondly invented" - and said, "Nope . . . apparently not, but apparently HE thinks so . . . " I told my dad about this episode, and he just rolled his eyes and said, "Well, that's Roy!"