Board Thread:Questions and Answers/@comment-42.60.140.19-20160311042006/@comment-26486243-20160323171046

The stat boosts are Eva, Acc, HP, ASW, LoS and sortie cost reduction.

Of all the ship classes out there the only one that uses all features is light cruisers - heavy cruisers and up don't have an ASW stat, while DDs get no mileage out of LoS as they cannot artillery spot.

Ultimately the bonuses aren't really that big though, given that the effect of levels are square rooted. It's more important to marry someone you want to spend the rest of your TTK life with. Unless, of course, you marry multiple girls.