Finished this a few days ago and wanted to share what I thought of it.
Firstly, I really enjoyed the style of writing. I know not everyone likes first person present stuff, but I found that it got me straight into the story and into the mind of Lauren. I think that she had had a difficult relationship with her sister. In some ways she loved and admired her too much, trying to copy her, wondering what she would think about things, and I think that subconsciously her sister had a hold over her that she wanted to break away from, and she finds something in Jay that helps her to do this. (I was a bit dubious about the bit where Lou has supposedly met Jay behind Lauren's back).
Dumpy was a character I hated at first, but then by the end I could see why he was like he was. Maria was horrible yet realistic and I have met people like her before.
Lolly - I absolutely loved her character, the strange mute child that seems to be Lauren's only friend.
Weirdly, I found something quite sexy and compelling about Jay. Did anyone else or was it just me? I loved being drawn into the self sufficiency thing and all the musical background to the novel and I think that this 'counter culture' mixed in with the mundanity of Lauren's desire to decorate the house and bring some order worked really well.
The ending wasn';t the one I wanted for Lauren but it did take me by surprise, and I did think about it for a while afterwards. I think that she is so captivated by Jay that she decides to do what it takes for him to get over his grief in the hope that one day he will love her as much as he loved Ruth.
Yes, there did seem to be things with Lou, the sister that weren't tied up at the end but I don't think they were necessary to the main story. Perhaps there might be a sequel? Althogh I'm not sure how that would work.