It was one year ago that I entered the Orthodox Church. To tackle the reasons behind this decision often proves an impossible task at this stage.
This said, I notice more people contemplating the decision. I offer a few considerations.
1) Anything worth doing is worth doing slowly
When one finally talks to an Orthodox priest, one will notice that he is no rush to "get this thing done" during the course of the calendar year. There is much wisdom to this. The transition from Catholicism to Orthodoxy can be exciting, however, the aftermath can fraught with confusion.
In my case, the whole process was decade, from the moment of making intellectual investigation, up until three years of regularly attending Divine Liturgy.
2) Immerse yourself in the liturgical life as much as possible
Whatever your parish has, make sure you attend. When one acclimates to the rhythm of Orthodox liturgy and prayer, one finds attempts at reintegrating to the Western liturgy somewhat jarring. If this happens, you've likely found your home.
3) The two are not the same
More often than not, you will hear many people from both the Catholic and Orthodox side talk about all of the similarities between the two. While points of affinity exist, Orthodoxy and Catholicism are two very different expressions of Christianity. To deny this is to deny oneself the fulfillment of either Orthodoxy or Catholicism.
4) There isn't much time for your prior liturgical or para-liturgical practice
Orthodox liturgy demands your attention, almost all of it. If you are of a liturgical mindset, be prepared to put away most of your well worn liturgical books. This will be done out of necessity. Orthodox liturgy requires yet more study, reflection, and contemplation. It is a world all its own and getting a firm intellectual grasp on it is somewhat more challenging than the Western liturgy. Orthodoxy is very protective of its liturgy, even from itself. The Orthodox liturgy is the source of belief and praxis; it conveys and spirituality and worldview that seem lost to the West and thus challenge much of our most intimate suppositions.
5) There is no "pure" church
When one enters Orthodoxy, one agrees to exchange one set of problems for another.
6) Don't try to run away from something
Whatever one might run away from in Catholciism, one will eventually find in Orthodoxy. As such, it is best not to move away from something, but rather move towards something.
7) Don't look back in anger
The transition will never be easy if one holds resentment or anger towards one's church of origin. One will never fully absorb Orthodoxy if one looks back with regret or vitriol upon one's former church. Again, the transition must be a transition towards something, not away from something.
8) One never abandons one's family of origin
As much as one may find the pull of Orthodoxy irresistible, one should always expect to have some concern for one's church of origin. There is no way around this. If one made a healthy transition, one will always have a sympathetic or compassionate eye turned towards ones prior religion. One will do this because, much to the consternation of some, that prior church played a pivotal role in forming you into person who would seek Orthodoxy