The tone is a little more ironic and colourful than Life on Mars, which might upset a few of the predecessor's fans. But those few will always be upset, and this show is incredibly worth it.
Alex, because she knows that she's most likely in a coma (having had Sam's tapes) is herself taking the whole scenario a little less seriously - and so should we. This show is brilliant in the way that it has fun with itself. In the first episode, there is one shot of Ray, Gene and Chris on a speedboat to the sound of No More Heroes, by the Stranglers. Ray has a close up where he is sort of half smiling, and the whole thing is so unapologetically 80's, with the right sense of self awareness. The opening credits, too, let you know that you should be having fun with this show.
As long as you're not looking for the same tone and style as Life on Mars (remember, this is a show about being in an 80s cop show, not a show about being in a 70's cop show), this is a brilliant show.