I've been smoking a pipe for over a decade and by accident, have managed to age some tins during this time. Is there a difference? In my opinion, not enough of one to dedicate time and worry to aging. If anything, I find blends to lose their appeal with age. Full Virginia Flake is one of them for me. I smoked a few tins of this that was at least 5 years old, probably much more, and found it very... underwhelming. Same goes for many other blends. To me, that "mellow" taste of age is muddy and frankly... boring. Most blenders blend for us to taste it fresh, so aging is more of a crapshoot than anything. Sometimes it's ok, and other times it's just stale (flavour wise).
Some people go nuts for age. Personally, I think it's something cooked up by tobacco blenders to get more sales. Here's looking at you GL Pease! Of course, I'm a big fan of his blends, so my conspiracy theories may be best left unsaid. But now I've said it. The power of suggestion, especially in marketing, is very... very strong. It's so strong that you'd do well to read a couple of books on it to see how often we're tricked into thinking certain things. Cigarettes don't cause cancer? The industry threw everything they had at that one, and for good reason, from a business perspective. Note: I don't think saying aged tobaccos are magnificent and that saying cigarettes don't cause cancer are even in the same ballpark, as far as devious marketing is concerned. Still, I think it's been trumped up to more than it is for economic reasons. It's clever, and the suggestion that it's going to be better is, well, good. Also, when you sit on some tins for 5+ years, I suspect we're more inclined to believe that they are better because of the effort (and sometimes, suffering) that we put into that age. Not many people will wait five years for something, with high expectation, and then say it's crap. It's just the way we work.
Hoarding tobacco from an economical perspective makes sense. It's only going to get more expensive, but that being said, I'm happy to fork over a few more bucks for fresh tobacco. I think it tastes better and is much more rich than the more muddled taste I get from a lot of age. But then again, some people like mud puddles over clear water, so what the hell do I know?
Hopefully that doesn't set your pants on fire...