This was one of my first yaoi series I ever read, and to this day, it remains one of my favorites. The story is interesting, but it's the relationship between the characters that really makes it worth reading. You get to see the two leads slowly get to know one another and fall in love, as opposed to so much yaoi where there is instant attraction and the whole "I'm not gay, so why am I getting aroused by this man?!" obsession dominates the story. Here, the mangaka takes the time to let the love unfold slowly and more realistically. Trust between partners as cops slowly leads into trust between friends and eventually, lovers.
Lest my gushing about the relationship bore you, there are some more great aspects to this manga. Bikky and Carol make such a fun pair, adding a bit of humor to a story that can sometimes get dark. Watching them "grow up" during the story is a treat as well! There is also a strong focus on the crime fighting aspect, so readers who like a bit of mystery would enjoy this series.
If you're looking for lots of nudity and hardcore yaoi action, this may not be the manga for you. If you enjoy yaoi because you like the relationship development, I would definitely recommend this series. I would also recommend it to anyone who is interested in trying out yaoi but might be scared off by too many sex scenes.