Higgins, I suppose this is a question of distinctions -- which ones I think are important, which ones you think are unimportant. There is no doubt Plotinus and his followers had some influence on Christian doctrine. Some say, for example, that the Triad of Plotinus influenced the doctrine of the Trinity. At any rate, most theologians, I think, would say that what neoplatonic notions made it into the canonical Christian worldview came via Saint Augustine. He was a profound thinker who lived about a century after Plotinus. Augustine converted to Christianity in adulthood after establishing himself as a brilliant philosopher already before that. He described all this in his Confessions, which I read long ago.
In the Confessions, Augustine explicitly discusses Plotinus. He even quotes exact phrases from Enneads, Plotinus's major work. This should not surprise us. After Plotinus left Egypt and came to Rome, he was the philosophical superstar of that time and place. I think the fairest statement is to say that Augustine read Plotinus (or Porphyry, his main intellectual heir) and used these texts, among others, to guide his musings and frame his argument.
There is a fundamental gulf between these two thinkers. Plotinus taught that one can meditate on the Divine (or the One, as he called it) and through this process alone achieve ultimate wisdom. Augustine looked at that and recoiled. In his view, such wisdom (or grace) was a gift from God that was undeserved by humans, and which they could do nothing to achieve, save open their minds and hope and pray for it. This issue is a huge part of his grappling with the problem of free will. This is not a trivial, nit-picking point -- it is central to understanding Augustine (and later to Luther and the Reformation).
What I'm saying, I suppose, is that specifics matter. As Ruv and AM have pointed out, any of us who ponder the meaning of things, and particularly if we turn our gaze inward, become mystics of a sort (or superstitious, in Ruv's formulation). The vocabulary of mystical experience, to the extent that there can be one, is inevitably shared. Late antiquity was a swirling mix of Eastern mystery cults -- Isis, etc. A majority of Romans saw Christianity this way. Christianity was far from the only game in town. The figure I recall is that only 7-8% of the entire empire was Christian at the time of the conversion of Constantine earlier in the 4th century, and these folks were all urban.
So of course concepts and even specific language was shared, but there are fundamental, crucial distinctions between Christian doctrine and Neoplatonic teaching, things best seen in the writings of Augustine, the Church figure otherwise most self-consciously aware of Neoplatonism. These distinctions -- free will and the nature of how enlightenment (or grace) can be achieved -- can't be dismissed by hand-waving.
And, although links are fine, I might be more persuaded by how you read, process, and formulate the gist of what these links say and mean.
