The region 2 complete series dvd set describes it as "where Hill Street Blues meets The Wire". I think it beats both shows. I watched the whole series when it originally aired. Every time the intro played and the phone rings at the end, with the voice answering the call saying, "homicide", it got my juices flowing as I knew I was about to be fully entertained.
The cast is about as good as it gets in a police procedural show. Andre Braugher's character is hands down the best police interrogator ever to grace the small screen. The extremely likeable Detctective John Munch was played by Richard Belzer for the entire series (all 122 episodes), and he also played the same character in 326 episodes of Law and Order: SVU. The two shows had some crossover episodes.
The episode 'The Subway' in season 6 is the best television episode I've ever watched, any series, any genre. The Subway currently holds a 9.6 rating on IMDB. It's as compelling as televsion can ever get.
Channel 4 used to show this back in the early 90s along with the NYPD: Blue. For me Homicide was by far the superior show. The book by David Simon is well worth reading, and a certain amount of fun can be had trying to map the real life detectives to their fictional TV counterparts.
Whilst I can't recall any particular storylines or too much detail, I do remember watching this series and thoroughly enjoying it. The content certainly wasn't glamorised iirc, it seemed pretty dark and what i'd imagine to be realistic.