I guess that's where we all differ. After trying both I choose NYGM for the very same reason that it seemed more realistic to me...
And anyway I suppose not many of us have really been there so it is more a feeling than anything else.
By the way sunk today my first cargo steamer from Sergbuto in NYGM 2.3. It looked nice, made a big boom (dunno what it was loaded with ?) but with 4,5m draft in heavy seas I wasn't 100 pro confident in my 3m deep torps... but went down OK with a 2 fish salvo from 700m away.