So first of all I really love shows shot in Vancouver. They're never actually set in Vancouver, but that's beside the point. This is supposed to be Seattle, which you know because it rains a lot. There's just something really distinctive about the color grading or the sky or trees or fog or whatever with Vancouver shows that I really love (starting with The X-Files).
I also appreciate really good opening credits sequences and a good soundtrack (which is apparently from the original Danish series). And I like all of the characters. I'm a fan of the whole subtle, understated acting thing. And I really like slow, unfolding stories (which has been a criticism of this show) that let you soak in moments and moods and stuff. (Insert obligatory "Mad Men's problem is that it's boring, not that it's slow" rant here)
The mystery/plot isn't that great. I'm generally pretty good at suspending disbelief and there was one scene (where Stan meets Bennet's wife at the hospital and they don't recognize each other) which was like... REALLY??? And there were several other things that were iffy, so it's going to be a disappointing show if you're watching it or the mystery and plot twists and whatnot.
The strength of the show is in the characters and their motivations and how they react to situations and how grief isn't just the overwrought wailing you see in a procedural when people find out their loved ones are dead. It's also when a mother is shopping at the supermarket and she sees her dead daughter's favourite cereal on the shelf.
I absolutely loved the two detectives working on the investigation. I know that Sarah doesn't really do much more than look intense/emotional most of the time, but it really works for me in conveying that she's processing what's going on and coming up with insights. And Holder is a really good foil for her and I appreciated the ambiguity of his character. It's weird, in the first episode you can hear a little bit of his Swedish accent, but for the rest of the series it just gets sort of absorbed into an indeterminate street-sounding accent.
Err, how did this show end up becoming Twin Peaks without the dancing dwarf? Not that I was disappointed, but... a high school "good girl" found in the water in Washington, was actually an escort who slept with lots of men and frequented a casino (OMG IT'S ONE EYED JACK'S!!!)? Since I wasn't that hooked by the mystery, the ending sat okay with me (knowing there's going to be a second season) but man would I have been annoyed if this had been the only season of the show.