3 best for me are:
*Rescuing down pilots and special ops missions
*S-class submarine is in and playable.
*Visual damage to ships (holes) and translucent water look superb
3 Worst
*No other submarines in the world apart from player - and no SUB AI AGAIN
(you want Ai subs, then you gotta go back to SH2 how stupid is that?)
*No other units can be added - or at least like sh3 it wont be possible until tools are developed, so much for being more "mod friendly"
*Multiplayer sounds ok - but i think a fully playable Japanese escort or two would have made it so much better.