SH2 was at its time the only option for a 3D submarines game, and the interaction with Destroyer Command had its appeal. But nowadays, for anyoone who never sweated and cried with it, and who has a PC that will run SH3, there is simply no comparison possible. Ignore SH2 and skip to SH3.
SH1 and Command Aces of the Deep are a different matter, though. If you value gameplay and ambient above graphics, you could still have some fun with either of them.
Good luck.
