I started on 688i, still play it, just finished all the original missions and campaigns again and now playing created scenarios. There are some really excellent ones.
For me SC with SCXIIc is a great sim. I alternate between 688i and SCXIIc. I play DW some, the subs, no aircraft, or the FFG, seldom play the Russian subs in SC or DW.
Just remember even with NCP 688i is an old sim, but I will always beleive it was a great sim. I wish they would do a new one based on the Virginia.
If you find you need help with 688i let me know.
Have fun,
Ron Banks MMCM(SS), USN(Ret)