I don't know nearly as much as I should about engines (I can just about name the important parts of my own) so I don't know whether that makes me a good or bad person to reply to this.
An old engine in an engine room is easier to see and get at, if you want to get to know it better and do your own repairs, but depending on what it is and how esoteric it is, it might be harder to find someone else to repair it. Having said that, there are people out there, and once you've found someone for your engine, you've found them. A modern engine is possibly harder to fix yourself if you're so inclined? Dunno, never had one.
Old engines sound nicer.
Engine rooms make good shed/drying space.
I couldn't bear to have a modern unit buzzing away under my feet. I'd much rather be deafened and asphyxiated (before someone else says it).
It's the same as anything else, when you find the right boat, the right engine will be the one that it's got.