I am an inquirer into the Orthodox faith myself (originally a Baptist), and I find that the more I investigate it, the more convinced I become that it is indeed the one, true catholic and apostolic Church set down by Jesus Christ. You want proof? I'll use the famous "Peter the rock" verse that Catholics believe form the basis for Petrine primacy. I'm sure you are familiar with it, but I'll quote for emphasis.
Matthew 16:18 "And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it."
Again, this verse is the one that the Roman Catholics use to justify Peter as establishing their Church. Unfortunately, before he established the Church of Rome, (although this claim has been contested) he had already established the Church of Antioch and had served as bishop there! Antioch, as you may well know, was and is still today one of the chief cornerstones of Orthodox Christianity. Christ saw Antioch as the origin of true Christianity, not Rome. (Acts 11:26: "The disciples were called Christians first at Antioch." )
The Catholic interpretation of this verse is inconsistent with history. If you look at the organization of the early church, you will see several autonomous and locally governed churches, as they exist today in the Orthodox Church. Although Rome and the See of Rome always held a special honor in the Church up until the great schism, this was due primarily to the power and influence associated with the region, not the supremacy or doctrinal authority of their bishop. It is also interesting to note that the Bishop of Rome wasn’t even allowed to attend the 5nd Ecumenical Council (553 AD) due to his support of the heretical Nestorianism movement. Surely if he were indeed the “Vicar of Christ” then he would have been present at one of the most important councils in the history of Church doctrinal development?
I believe that if you create a theological timeline comparing Orthodox Christianity vs. Roman Catholicism you will come to the conclusion that where Roman Catholicism differs from Eastern Orthodoxy, Orthodoxy had in fact preserved the authentic tradition. This is particulary evident in authentic Christian liturgical ethos and the development of the historic faith.
EO- Full immersion (original)
RC- Sprinkling (later modification)
Sign of the Cross
EO- Right to left (original)
RC- left to right (later modification)
EO - The Holy Spirit proceeds from the Father (original)
RC - The Holy Spirit proceeds from the Father AND the Son (later addition, “the Filioque“)
This should be enough to get you started. I could go on for hours!
I can add these other elements to this post that I found partially answered your question you offered to me, dear militantsparrow:
EO - Communion under both species (cfr. Christ's words: "Take and drink all of it" in the Gospels)
RC - Communion under bread only
EO - Both secular and regular clergy (cfr. Paul's words on married presbyters and deacons, together with his appreciation for celibacy)
RC - Regular (i.e. celibate) clergy only
EO - Three Sees established by st Peter the Prince of the Apostles: Rome, Alexandria and Antioch (cfr. pope Gregory the Great's letter to his fellow patriarchs)
RC - Only one See established as successor to Peter, the Church of Rome
EO - Baptism, chrismation and communion always given at once even to infant (see hippolitus of Rome, Ambrose of Milan and tens of other W and E fathers)
RC - Baptism, communion and confirmation given separately at different ages and in a different order then the traditional one
EO - The true 8th Ecumenical Council is that of 879-880 AD (cfr its Horos and the Epistle of Pope John VIII that put Photios back on the chair of Constantinople)
RC - The true 8th Ecumenical Council is the Robber Council of 869-870 AD
EO - All bishops are icons of Christ (cfr st Ignatius of Antioch, of thrice blessed memory)
RC - The Pope is the only vicar of Christ and all bishops are his suffraganeans
EO - Apostolic tradition of praying at DL ad Orientem (st John Chrysostom wrote that it's an apostolic tradition)
RC - Protestant-style prayers at Mass ad populum (where the priest replaces Christ at the altar)
EO - Chants without instruments at DL (agreed by all Church Fathers that dealt with this matter)
RC - Chants with instruments (organ, and recently guitars, bongos etc) and adoption of Protestant gospel music
I think these points would be of much interest in persuading you how Orthodoxy is the only true Catholic and Apostolic Church!!!