I don't know why this show gets so much hate, but there's no way it's because of the actors.
It's been a long time since I've watched anything of this standard. Sure, the show no doubt has its flaws, as all shows do. I've seen people complain about historical inaccuracies, and they're probably right. That doesn't spoil anything for me, though. I didn't expect a documentary.
I loved the way the characters' relationships were portrayed, and they were all believable and heartwarming. I loved that British sense of humour from the very first episode and all through the series.
I absolutely adored DI Chandler - he is, hands down, the most relatable character I have ever seen on TV. I don't suffer from OCD (I periodically have a very mild form of it), but I am autistic, and even though he isn't necessarily supposed to be, I see so many of my own traits in him. He is the sweetest and most adorable, socially awkward character I have ever seen, and Rupert Penry-Jones did an excellent job of portraying him. His issues are realistic, and I loved how Miles supported him instead of ridiculing him or just telling him to get help.
I loved everything about this show, and the only thing I missed was a fifth season, because the fourth left a few things hanging.