I think there is some hometown cringe going on. I thought it was a very good show with a complex plot and complex family relationships .I thought the main character was excellent. We grew to know and love her and her children. We were invited into a real family, doing believable things. I cared for the characters.
Dealing with cystic fibrosis without grandstanding it, just quietly demonstrating the work required was noble and nowhere were issues overstated.
For me not living in Ireland, the scenery and different way of doing things deepens interest. The intertwining of the past and present keep the tension at a fairly high level. At several points when you feel the crime is about to be solved, they wriggle out of it but always in a believable way, easing the tension momentarily but not for long.
Did think it ended without a real resolution but I thought that was because a second series was planned. Is this not so?