It's a great story even if it hurt my head a little. I am second generation Irish. My grandparents (yes all 4 and no not the same boat) came over in the 1930 and 1950's respectively. I gained a great deal of Irish culture from them and it still didn't help me with this story. There is a great deal of dimensional jumping. I think this did me in. I wasn't able to wrap my head around what was happening. Which makes it difficult to understand where the story is heading.
That's about it. I don't think I'll go searching for more books by these authors. But I won't shut them down without a thorough look-see.