This reads like a perfect mixture of Hilary McKay and Jane Austen. (Style-wise and situation-wise. For instance, doesn't "Almighty Lou" remind you of Lady Catherine?) I had a lot of fun with the story, the characters and the writing - especially the effortlessly witty, but natural dialogues - and I want to get my hands on How to Say Goodbye in Robot even more than before now.
As the description already reveals, "The Confessions" are told from different points of view. I love that, but not everybody does. If you are put off by multi-angled stories because you are bored by repetitions, you do not need to skip this one. The plot touches the same moments now and then (because naturally the sisters meet and there are certain key situations), but basically each sister has her own confession to make, her own voice and her own life. Everything is tangled masterfully and the end surprised me beautifully. (I snorted my self into laughter - and consequently startled a couple of commuters at my bus-stop.)