I received a build (says "alpha 3" but seems more like a late beta, as the game is due late next month) of EA's Sub Command, a modern sub sim being done by Sonalysts. It's kinda like 688(i) times three, as you get three campaigns, one for each of the SSN 21 Seawolf, the 688(i), and the Akula (a Russian sub). There seem to be more random elements in the missions, and a lot more polish than the earlier game.

I'll be happy to answer anyone's questions if there are any sub fans out there.`

How do you find the sonar suite ? Has it changed much since 688(i) ?

Well you have three of them now, but the two US suites are similar; the Akula uses a rather different system. It's pretty much the same since 688(i) though. If you choose to handle sonar yourself (and why would you not?) it's the same manipulations, basically.