I just finished watching it. Great show - right up there with Luther for me. The length seemed just right - there wasn't a lot of repetition or stretching plot lines out. It really moved along. I like that about British shows - a season's worth of shows can be 4, 6, 8 or more episodes. The Luther seasons are always too short for me (6, 6 & 4 episodes), but in the end, I'd rather be left wishing there was more than watching a show drag because they're just filling time.