What about it, indeed?
I know very little about Orthodoxy, really. I know that it can make a legitimate claim to being the real flagship of historic Christianity, as the RCC does. I know that it differs from Western Christianity in a number of ways, not least of which is the celebration of Easter.
One difference that is significant is the issue fo the filioque. That is the term gien to the western doctrine of "double procession," meaning that, as a matter of relationship, the Holy Spirit "proceeds" from both the Father and the Son. The Orthodox deny that the Spirit proceeds frm the Son.
Is that important? On the surface you would think it should be, what with it dealing with the nature of God. But I honestly don't see it being about the nature of God so much as a description of the internal relationships of the Trinity. I can't say I regard such a description as being a central element of the faith. Besides, I can't find much in the Bible that even speaks to the question of the filioque, let alone anything that supports it.
Yet there is also much about Orthdoxy that appeals to me. I like the way the colegial manner in which tye govern themselves. I appreciate that their theology generally deals with mystery; if you go to a service you will be struck with awe and wonder if you're not immediately confused by what you see. There is a greater sense of the sacred in an EO service than in your typical evangelical worship time. It is also somewhat darker, in many sense of that word.
In the end though, Eatern Orthdoxy is a bit to comfortable with the doctrinal developments that we see in the RCC for me to be comfortable with it. The Mariology is not as developed, neither is the doctrine of the saints. The fact that it deals with mystery makes it hesitant to affirm things that it is unsure of, but also makes it hesitant to deny things. When speaking of questionable matters, I am fine with the hesitancy to affirm, but the hestiancy to deny strikes me dangerous. In terms of guarding truth, the hesitation to deny error can be costly.