A particular part that struck me was the female actor's ability to show what it is like to be in an abusive relationship. This part struck me long after watching it.
Generally, I found the series very well acted, compelling story and rather tragic.
It's certainly worth a watch.
I do not really understand the review that saw it as offensive to people from Liverpool. Further, I don't think it was trying to be 'breaking bad' just because it had drugs in it. I think that is a rather shallow interpretation.