So I finally sat down and read this, after planning to for quite a long while. I've seen people raving about it here in comments, and to some degree I can see why. There's some good stuff in there.
But holy crap, is it so melodramatic! Maybe it's a function of reading it all at once rather than as the chapters come out, but it feels like all the time one or the other of them says some little innocuous thing that's vaguely related to the brother, and everyone's doing a dramatic turn to the camera while the music goes DUN DUN DUNNNN!!!!! And the endless angst about how the other person views them, or whether this is a normal reaction or what have you, and I can't see how they don't spend their time exhausted from all the worry.
Plus of course the continual romance-coding of their interactions, which is simultaneously really nice and a bit frustrating since it seems like it'll never, ever happen. I mean these two act more like a committed couple sometimes than the girls from A Room For Two, and that's really saying something. And I'm pretty sure the author is aware of how it looks, given they have characters within the story taking note of that dynamic.
Still, it's a good read for all of it.