Addictive viewing... It passed me by when it first came out, but I followed up a friend's recommendation and was more than happy I did so.
Watching it prompted me to read the books; so far three in the series from Richard Morgan. I can say that there are some fundamental differences in the plot and characterisations between the TV series and the book that will irritate fans and made me wonder how they will resolve them if they go on to adapt the next two books.
If you are not a fan of the book, then you should find the TV series is phenomenally good.
After looking at the various reviews and comments online, it seems that the "creator" intended to portray women in strong roles; if this is true, then it is an other example of visual media's highjacking someone else's story to preach to us with their own social agenda. I wish they wouldn't do that.
Setting those collateral gripes aside; I can say that the TV series is very watchable and grips you from start to finish.
Note that it is very violent and gory, so be warned...