On the one hand, the pacing is pretty even and the plot's linear enough that the story (such as it is) holds together. There's implied caveats in that last sentence because it really is mostly the momentum of the thing that saves it, more than anything particularly compelling about the storyline itself.
The character explorations were nice: Lincoln is extended beyond his tragic past by his sister's family and his responsibilities to them, and Jake's GFY drama is somehow leavened by the ludicrousness of the whole thing. They were both pretty likeable, too, which helped offset all the angst. The writing is decent and doesn't stray too far into weeping adjectives, which I would have totally excused given the premise.
On the other hand, the mystery in the story is provided by the most absurd thing ever, and I was all the wrong kinds of gleeful about the ending, which really just needed a butler and a library to tip it over into total farce.
I'd recommend it for the emotional journey the two characters have to battle through and nothing else. Block out everything but Jay and Lincoln discovering their love through body fluids and it'll all work out.