I found a web page called "From Buddhism to Orthodox Christianity" which made several good points;http://www.angelfire.com/pa3/OldWorldBasic/Buddhism_to_Orthodoxy.htm
I am one of at least 8 people that I know who have become Orthodox Christians after having been Tibetan (usually Nyingmapa) or Zen Buddhists. There is a good possibility that there will soon be a book with the stories of such people, and how their conversion took place. I can offer you a few sample perceptions that I have developed on the way as to why Orthodox Christianity makes sense to Buddhists:
• Buddhism has always been primarily monastic and ascetic in nature, with an emphasis on spiritual practice and development more than just mental assent to a list of truths. There is an organic unity between understanding of precepts and the quality of practice in Buddhism that serves well when learning about Orthodoxy.
• Buddhism has always had some form of ‘iconography’.
• Buddhists venerate the lives of ascetics, relics and ‘saints’.
• Buddhists (at least the Tibetans) have highly complex and developed forms of liturgical practice, including chanting, incense, etc. (e.g. they aren't intimidated by the typicon :-))
• Buddhists understand that it is wise not to live for the present life, but to struggle for the future one.
• Buddhists understand the value of dispassion and mental stillness.
• Americans who become Buddhists usually are fervent spiritual seekers, who get used to struggling with foreign languages and cultures, and pushing themselves outside of their ‘comfort zone’ in order to imbibe a deeper spiritual life.
• Buddhists are already used to the idea that fervently seeking spiritual growth will cause pain in the legs :-) :-).
Now as to why someone moves from Buddhism to Orthodoxy - everyone's story is different - some are miraculous - some are frightening - some are fairly ordinary. But a common denominator seems to be that; if a person has even the smallest history of knowledge of Christ before becoming a Buddhist, then even the smallest of such impressions, even from early childhood, will cause a Buddhist to reach a point beyond which they cannot grow as a Buddhist. There are Buddhist practices that serve to ‘open the heart’. Such a practice will often not work for one whose heart has been visited even briefly by Christ - their heart will open only for Him. More than one Buddhist has caught himself chanting a mantra that he or she had previously chanted over 100,000 times, that somehow, one day turns into ‘Lord have mercy’. And He does have mercy!
Fr Seraphim (Rose), also a convert from Buddhism to Orthodox Christianity, said of Buddhism, ‘It’s fine as far as it goes, but it does not go far enough’.