anyone seen Luther?

Has anyone seen the show “Luther”? I hear it’s okay, but I don’t know if it’s old or new or what. Im on season 1 episode 4 (almost finished with it) and here are 2 seasons on netfilx… Is it seriously only 2 seasons long? Or does Netflix not have the rest? Anyway,how is it overall? Im kinda liking it so far, but it’s kinda weird at times… I hear some epidoes are hard to watch… :o