What divides us is Chalcedon and a lot of bad history that happened afterwards.
I have yet to hear anyone lay out any substantive theological differences. In fact, a couple of years ago in a thread in the private forum, I asked if anyone could give any substantive differences. I think all I got was an OO saying the EO's have toll houses and that they believe in universal salvation. The problem with that answer, however, was that only some EO's believe in toll houses and there's only one EO that anyone knows of who believes in universal salvation. No other substantive differences were offered.
You might want to click on the Chalcedon tag below and read through some of the threads to get a feel for what that's all about. Basically, the OO's say Christ has one nature which is fully divine and fully human and the EO's say Christ has two natures, one divine and one human. Some EO's like to accuse the OO's of believing that Christ is not fully human, but that's a bunch of baloney. Similarly, some OO's like to accuse the EO's of believing that the two natures operate separately as two different persons, but that is also false.