Based on what the OP said, the nature of the gun, type of gun, "shoot it a ton" (more chances for something to occur) "pass down to generations", etc etc etc, I think SS is the only choice here.
Given everything mentioned, a blue gun could easily look like crap in not so long a time. Now of course, blue doesn't really rust on its own (I know blue is basically a type of rust) and blue doesn't wear on its own, but blue is DEFINITELY less durable than SS. I say definitely spend the extra few $$$ and get SS in this situation.
Winchester 73, the TFL user that won the west