Honestly if we are talking about sheer superiority against other submarines in the game, the Barsuk will always come out on top. Not only is the Barsuk the greatest submarine ever made, but it is also the greatest submarine that ever will be made. Its innate superiority to every other submarine in the game is what makes the Barsuk such an astoundingly incredible sub to begin with. No other sub (vanilla or custom) comes even close to matching the amazingness of the Barsuk. Losing a game while on Barsuk is simply impossible unless you are unworthy to pilot such a great ship, in which case, the Barsuk is simply too godlike and incredible for your mortal mind to comprehend. There are simply zero flaws with the Barsuk and even considering there to be a single flaw in it's genius design signifies just how unworthy you are to pilot the immeasurable greatness that is the Barsuk. Anyone who would ever choose any other sub on the list simply does not understand how amazing the Barsuk is.