I waited until I had the time to sit down and sink my teeth into this, and did I ever relish its taste.
The slow building relationship between Snape and Harry in this fic is deeply satisfying. While I liked the Harry/Draco, I was reading quickly for those parts, anticipating Harry going back to his sitting room so he could talk to portrait!Snape more. The plot was ingenious and a fabulous way of bringing Snape back -- but it wasn't cheap and Snape's reasoning was well-explained.
I love that your Snape is not a saint. In light of DH, some people feel they need to make him that way, but your Snape -- even though searching to start anew -- does what he has to do.
The scene towards the end...yes, THE scene...in which feelings are finally verbally actualized was fucking amazing.