Hi sordid,
Concerning just SHIII, I knew very little of the German Navy and U-Boats before playing. However after getting hooked it got me interested in the history and I have spent a lot of time reading books and websites about u-boats and the people who commanded and sailed in them. For me, its been a great experience and I have learnt a lot about what the German sailors went through and what they achieved.
Therefore I have no problems with playing the side of the Germans as I feel that the game has allowed me to understand a part of history a little better and prompted me to learn more.
Cheers
Stan.
ps. I am English and your English is very good
pps. Eichenlaub a very good read