Which mod should I use?
 

After many years sitting on my shelf I finally decided to pull SH4 out and use it. I was having to much fun with SH3 and decided to stick there. I had no idea of the varied amounts of mods that had been put out for SH4, if I had read this forum I would have noticed. I'm not a hard-core player but I love eye-candy. Could you folks give a suggestion on which mod would appeal to an average player? I so hate seeing that arrow marking which way I am going on the ocean in my external view! One other problem I have encountered is in regard to the uboat missions. I bought it a D2D and when I try in install it it doesn't accept the code I was given, is it only good for a certain amount of time or something?

For the PTO:

TMO (you might want to add the optional mod to lower the AI ability)

RFB

FotRS

For the first two, RSRDC on top for the campaign would be my suggestion.

My suggestion on which mod to use:
All of them.

Try them each out, see what you like, and what you don't. It's the only way to find out which one will work best for you.