I've only just started watching this show. It has been on sky here which I don't have so it has taken until now and series one box set to get me started.
I must say, after 4 episodes in, I am finding it quite compelling. The characters are interesting and the setting very wet and dirty which I like. McShane steals the show of course. On this evidence he would have made a terrific spaghetti villain. But the others are all doing a fine job and the storylines are interweaving well.
My one criticism, at the risk of sounding prudish, is that I find the level of swearing a bit gratuitous and after the first couple of times really doesn't add anything to the piece. I don't mind swearing, I consider it a very valuable and pleasurable part of our language. But in this context I don't think it is neccesary to go with it so relentlessly. Not stopping me enjoying the show mind you, but it does mean I have to restrict my viewing to times when everyone else in the house are safely asleep.