I thought Hinterland was entertaining and intelligently written overall. The story lines held my attention and the investigative team he works with are people I cared bout.
But DCI Mathias himself comes close to being the stereotypical detective who has personal problems and often breaks the rules on the job, getting himself into hot water in the process with his superiors and his family. He doesn't quite reach the full cliche of the dangerous, outside the lines police inspector, however, because he maintains a healthy relationship with his daughter, and he mostly has a good rapport with his team. And at least he seems to regret his mistakes, which mostly center around his handling of suspects and witnesses.
Many police detective shows follow one of two paths: either they solve a crime every episode or else it takes the entire series to solve it. Hinterland throws a bit of a curve, because the plot of at least one of the crimes is carried over to all three series while other plots are resolved. Those lingering plot lines fade to the background certainly, but there it percolates and surfaces in small ways, waiting to emerge once gain as a major plot. I also like the settings of this series.
So I recommend this show, though if you have a few of the better mystery series on your viewing list, I wouldn't go so far as to suggest you bump them and watch this first.