Hi and welcome mate.
My preference is SH4, but probably only because my current set up wont run SH5!....
You can make the game as easy or as hard as you wish, I myself have started on very easy settings until I get more familiar with the game and then will introduce a lot more ' realism' later on.
Whatever, the Silent Hunter games are all fascinating and highly addictive, enjoy, and look around Subsim if you have any problems, just about everything is well covered by these guys!
