US DD's,Mini cruisers with 5" machine guns with the added bonus of smoke, speed boost and close and personal torpedo's.
I started with the IJN DD's due to the appeal of the longer range torpedoes, but it got quite boring after a while and decided to start the US DD line, and to my surprise they are actually quite fun to play, just got to adjust the play style because the IJN method of operation absolutely doesn't work with US DD's.
Personally at the start i either cap or hunt and harass enemy DD's, mid game start looking for distracted ships and lay down HE shells to score fires, get closer to drop torpedoes if it's relatively safe ( aka no cruiser or two around )
Only at the Nicholas so far but i am having a lot of fun.