FanficRecs Good writing, but too saccharine for my taste.
I enjoyed the first chapter-and-a-half, but upon meeting Harry, Snape drifts rapidly out of character. His confrontation with Petunia, while satisfying, is clearly what the author (and every other reader through the years) wanted to say to Petunia, and is completely at odds with Snape's usual voice. His kindness to Harry is implausible: bitterness like Snape's does not vanish overnight, even if it's no longer directed at Harry personally.
The writing is good and visual, with some interesting concepts, so if you have a high tolerance for sugar you might still enjoy this. I had to give up at Gringotts, when Snape makes an unprovoked pun.
FanficRecs Good but not without flaws
Good: Very good prose in my opinion. Fleshing out of OC's, it's a fun read in general. Not overly dark...in fact, it's almost the opposite.
Bad: Problems are resolved way too easily, there's very little lasting conflict in this story, it's a feel-good tale. Prepare for a LOT of Draco in Leather Pants of Snape.
FanficRecs Lovely
Not the best story ever (the problems are fixed a bit too neatly), but does a good job of showing how Harry and Snape's relationship would be different if they had met under better circumstances.
FanficRecs ridiculously optimistic but worth it
Nearly every problem in the books is solved in one way or another, some characters are straddling the line between In Character and Out of Character, if not outright crossing it, and it's kind of ridiculous how almost every character gets a happy ending (one character technically gets TWO happy endings), but if you suspend your disbelief willingly, it's still a very nice read.
Snape, one of the main characters, and so, the most noticeable in this aspect, is at times out of character -which is kind of necessary to make the premise of him bonding with Harry work-, but it's still very satisfying to see him defending and protecting Harry, along with other adults, and encouraging a better atmosphere in the school, after the messes that Fridge Horror points out actually went on in Hogwarts in canon. It's even vindicating, you could say.
Both this fic and its sequel close the story very nicely, leaving you with a nice, warm, fuzzy feeling.
FanficRecs Uninspired
The fic bends over backward to make Snape the protagonist, which would be less of a problem if the writer had made an effort to be subtle about it. Significant parts of canon were changed, everything from Potter family history to 1991 British law regarding child neglect and abuse (largely ineffectual unless a death occurs by which it would be too late. Even then, though neglect is a type of abuse, what Harry suffered in canon would not have been enough to get him attention in an overwhelmed system). The writing overall was very hamfisted and the characters two dimensional caricatures of what the writer needed them to be to carry the plot. I stopped reading at chapter 9.