The show is terrific - largely due to not only the writing, but the central performances by Andrew Lincoln and the superlative Lesley Sharp. It's very interesting, because Lesley acts without appearing to; she has a knack of drawing you in to what is really a very ordinary character with an extraordinary prowess. And she doesn't like it. This is no 'wow isn't having these powers terrific' show. For the most part she hates it. Lesley is totally convincing in the part.
There is a real knack to doing ordinary,whilst being extraordinary at the same time.
I haven't seen the entire two series yet, but what I have seen is perfectly pitched; the roles are played to perfection and there's a healthy cynicism going on, which goes beyond the slickness of Mulder & Scully and into something mundane yet real and more believable.
Plus it also shows what the pressures must be if you do have this 'gift' of being able to see and interact with the spirit world.
Great show; great acting and great to watch.