1. It is a very personal experience, but not a solitary one. This seems to indicate that there could be a social nature to mysticism for Augustine -- unlike Plotinus' "flight from the alone to the Alone." Furthermore, it is an experience had with a woman, something that Plotinus would have not likely countenanced.
2. The report is of ecstasy or rapture. It is a "foretaste of heaven" -- a phrase very unusual in the Greek mystical tradition, but quite common for Augustine. If ecstasy went on forever, it would be indistinguishable from the joys of heaven. There is therefore a strong contrast for Augustine between this life and the next, while for the Greek Fathers death seems almost incidental.
3. There is a way of ascent given here. It mirrors Plotinus' account, with some differences. Plotinus talks in terms of light flooding the soul; Augustine talks in terms of the soul passing out of itself to touch the eternal wisdom. Nevertheless, there is a definite debt to Plotinus.
The difference is important, though. It is the difference between the Greek idea that the natural end of human life is the culmination of the human longing for God, and the more Christian notion that it is something God gives us.
The second place is Confessions 10, where he reflects on what it is he loves when he loves God. This leads to a long discussion of memory. It is important to note that, for Augustine, memory encompasses the whole mind, both conscious and unconscious. He says as much several times. The whole universe is embraced by the memory. Memory is, therefore, potentially the whole spiritual world. And, the practice required to draw on the memory is spiritual practice.
As in the later work De Trinitate, the goal is true knowledge of the self, so that one can know God. The memory is not God, nor does it contain God, but it strains and almost touches God. God condescends to touch memory. The soul passes through creation and rises above it. This parallels Plotinus, but is not identical. For one thing, Augustine's God cares for the soul's search, and administers grace. This grace is administered through a mediator, the incarnation of the Word. This is also different from Plotinus.
One important feature of Augustine's discussion of memory is at the end of Book 10, where he goes through the various senses. He has a kind of purgation happening here, for the order of the senses is away from the body (touch/sex - ch 30; taste - ch 31; smell - ch 32; sound - ch 33; sight - ch 34). The body is being progressively abandoned. Chapter 35 talks about the temptations of the Word -- the interpreted. It is the temptation of knowledge, the answer to which is grace.
The problem for the human is that we cannot go on this path without the help of God. The path can only be taken in humility, but we are essentially proud people. God must give us humility, so that we can know him.