Buying modern would be a lot simpler since you can get it from the AD and at a fixed price.
Buying vintage means investing hours of painstaking research into vintage pieces. And that still does not include the time to actually find one available for sale! Prices can also vary wildly.
This is part of the point of this thread. Most people can’t get a modern Ed White from an AD.
If for the same price I can have the old one in very good condition then that's the choice I would make.
IF is the biggest word in the dictionary, the trick is getting a vintage 321 in very good condition and having access to a good watch person when it needs some work. It just is getting harder and harder, at least in my experience. It all depends on your collecting approach and mentality.