I enjoyed this, partly, I think, because I'd never seen an Irish police thriller before. The main plot was gripping and well acted. I thought the ending was very well executed and certainly doesn't need to imply a second series, as some reviewers have said.
On the negative side, I found the family soap opera a bit tedious. The stories with the three children had nothing to do with the main plot. It's as if there were two competing programme ideas and someone had the not-so-bright idea of putting them both into one.
The English police scenes did not ring true at all and the histrionic outburst near the end was bizarre. Why was the superintendent (?) in charge of the case referred to as the "commissioner". It made no sense. The accents weren't always quite right either.