Perhaps the clearest indicator that Daughter (to me at least) ae more than a buzzy, over-hyped new London band, is the fact that I am very eager to here what they do next. If You Leave is by no means perfect, but it hints at a great potential to actually build a progressive career. By contrast, I can't really see many people caring about the third album release of Haim, AlunaGeorge etc.
I've met people who've been put of by Daughter as they've heard they're too "folky". That's bizarre, it's been mentioned on here that they sound best when the guitars have a Flying Saucer Attacks-feel to them, though the quiter songs do add another shade to the whole album. I quite like the Mazzy Star comparisons also, and it'd be great if they could foster a consistency similar to Low's