Since I was a fan of Colm Toibin's Brooklyn I approached Nora Webster with an expectation of beautiful storytelling, characters you could care about and a good plot. 
But let me say it now. Nora Webster is no Brooklyn.
Nora is a widow who feels oppressed by the well-meaning pity of the Irish community that surrounds her and knows her so well. But she isn't a victim, she is a well-rounded character who has a sharp tongue, often doesn't care about how her actions and words might affect others and is slightly feared by her family. She is often ungrateful and haughty. 
So what is this story about? What arc can we expect for Nora's growth? Will she find that music opens her soul or helps her relate to others? Will she become a great star? Will she find love and friendship? Well all I can say is that Colm Toibin is writing about life. Real people with flaws, real life stories. Crises come and go and lead to nothing. Real life isn't about arcs. 
But here's the thing. As a reader I wanted an arc, a moral, a conclusion, a result. Nora and Toibin offer us little to satisfy these needs. Finishing the last page I rushed to the end with a sense of frustration. Why did I spend all those hours reading this book, spending time with this spiky widow when I was offered nothing in return. 
In Brookyn we get a story, and a moral of obligation and prior engagement. There is a choice to be made that keeps you enthralled and a resolution to be expected. In Nora Webster art imitates life but the result is there is no story, no resolution, only your own frustration that nothing has happened. 
I give Nora Webster a 5/10 for these reasons. It's simply not my cup of tea.