I wouldn’t say they are the same, nor would they, but they have many similarities.
I think it's safe to say that their theology, but not ecclesiology, is similar. As noted, the Orthodox do not believe that any bishop has universal jurisdiction over the entire church, as Roman Catholics do. Despite their differences, the Roman church considers Orthodox sacraments valid and recognizes the Orthodox have apostolic succession; the Orthodox, on the other hand, do not view Catholic sacraments as valid.
In a general sense, Orthodox theology is not as rationalistic as Western Christianity, either Roman Catholiciam nor most Protestant sects. You won't find the equivalent of an Aquinas, parsing sentences and slicing definitions, in Orthodoxy. Orthodox believe in transubstantiation, but by and large they simply accept that it is true and don't spend too much effort trying to define exactly how it or when it happens, which is something they don't consider important and that God hasn't told them.
Unlike many Protestants, neither care for the Hebrew OT (Masoretic Text), which does not include the Apocrypha.
The standard Bible of the Greek Orthodox is the LXX (for the Old Testament) and a Byzantine text (for the New Testament). The various ethnic Orthodox churches (Russian, etc.) have liturgies and Bibles in their own languages, which have their own translational histories. (There is no officially sanctioned translation in English, although several Bibles are used. The New King James New Testament is the text found on the American syn) The Orthodox churches have varying lists of deuterocanonical books, in general including more than the Roman church.