Originally Posted by Monarch
Why not use a bit of both?
Few games with the H39, then a few games with the O Pro II '42. The H39 will have no exp penalty so there is that to consider however the O Pro II '42 is a monster.
OPro II is a monster.
Opro II 1942 is a monster with an extra knot and support slot.
However, since you normally calculate your AA gunners leveling as not rotating lvl 89-120 (H39 and H44 keep the AA on), they are normally going to be there all the time. Opro AA is lesser than H39, so you won't enjoy them as much in the O2 42.
As suggested, get that thing out every once in a while for a bit of fun. O2 is quite aggressive in style for a KM ship.