I got the Monaghan a while back in those containers you get from the completing public test missions. I ignored it for a time because I'm not much of a DD player. I started playing it more recently and really enjoy it. It is without a doubt my favorite DD, though I still don't play the class that much.
I run the B hull which has 9.2 km. torpedoes. With a stealthy torpedo build you can have a comfortable range from which you are undetectable but can still hit enemy ships. I also find it's AA is also good for it's class. I've had several games in which I've racked up 20 or so plane kills against lower tier CV's. A note though, in it's B hull configuration it is a terrible gunboat.
Overall I enjoy using the ship to hit flanks and CV snipe.