I remember when watch collecting used to be about this:
Too much focus on what value a watch will fetch. If the OP is serious about being interested in the 321, then all that matters is the actual 321. That’s what this piece is about. I mean, just look at it! I do all the time. The rest of the watch slaughters the regular Speedmaster as well.
As for comparison to the Daytona, the 321 is just a superior watch on all levels except water resistance and hype (which to me is a bonus). I had both, I no longer have the Daytona. Nor a desire for it any longer. The Daytona is miss represented as a special watch because it’s hard to get a retail and the hype/market. The 321 Speedy IS a special watch. Period.