I enjoyed this book enormously. It is, in structure, a pretty standard chalk-and-cheese romantic comedy but differs from a good many romantic comedies in that it is genuinely very funny and also rather touching in places.
The narrator, the geeky Don, is somewhere on the Asperger's spectrum and much of the humour of the book derives from his extremely literal take on things and his inability to read social situations. This has the potential to be cringe-makingly embarrassing but isn't - the narrative voice is so well done and Don such an engaging character that it's simply charming and often very funny. To give just one example, "I immediately recognised Julie...from Gene's description: 'blonde with big tits." In fact her breasts were probably no more than one and a half standard deviations from the mean size for her body weight and hardly an identifying feature..."
Other characters are well-drawn - so much so that you don't really notice that they're from RomCom Central Casting: the louche, lascivious best friend (Gene in the above extract), the rebellious, slightly kooky romantic interest, the disapproving boss...they're all there. But so what? They are so well done and the story so well told that I didn't even spot the Regulation Cast until after I'd finished.
There have been some very good Asperger's or Asperger's-like narrators in books - The Curious Incident..., obviously, but also The Universe vs Alex Woods The Universe Versus Alex Woods and even Kiss Me First Kiss Me First, which I didn't enjoy much as a book but has an excellent narrative voice. The bar is set pretty high, therefore, but this matches up extremely well. It's not packed with meaning and deep human insight (it's not supposed to be), but there's far more substance to it than just a fluffy, disposable RomCom.
In short, this is readable, engaging and funny. I made a spectacle of myself in public more than once by laughing out loud at the book, and I warmly recommend it.