Pretty much any oolong has the potential to age, particularly if it doesn't have a lot of moisture content (such as if it's roasted).
A lot of aged oolong is re-roasted over the years, but others just get tucked away, forgotten about, and then rediscovered years later.
Wuyi Yancha, such as Shui Xian, Rou Gui, Da Hong Pao, and the rest are always better aged and usually relatively heavily roasted compared to other oolongs. Whether heavily roasted or not, it's safe to say that it takes a few years for the flavors to balance out. The heaver roasted ones will have a lot of the roasted (or "charcoal" flavor) that needs to mellow out, and the younger ones will have something of a cacophony of flavors competing for attention that need to mellow to a balance.
Aged yancha will take on a particularly defining refined balance and texture that just can't be found in younger yancha, though some will need to be brewed right to get. Personally I just can't get into young yancha, and if you look at the descriptions at places like Jing's it doesn't even really seem to be considered. For some comparisons you can visit my Rou Gui comparison blog post here
Green oolongs will be the most fragrant when they're fresh. After some time the aroma will start to diminish, however. As oolong ages it tends to change from floral to fruity.
As far as what determines whether something will age well or not, I think that's a bit like predicting puerh; one can really only draw on experience, and then it's still just speculation in the end. There are a lot of unknown variables and schools of thought. The more heavily roasted, however, the more likely it is to age well. With yancha it's almost a given, though I don't know about the greener ones.
Of course these are different vendors, and the first one has an extra "Wang" in its name, so maybe this is not a good comparison. My guess is they are also different grades of tea?
That seems to be the case, and "wang" does mean "king" which usually denotes a higher grade.
Take a look at Jing's selection and you will see two different grades of Da Hong Pao for very different prices. Each farm will usually produce batches at different grades. These higher grades are usually evident in the dry leaf being full (few, if any broken leaves), more carefully processed, and of consistent size - you can see this in the pics of the two Rou Gui's from Seven Cups in my blog post above. They will carefully separate out the (relatively few) best leaves to carefully craft into the higher grades, and use the bulk that's left to produce the cheaper stuff in quantity.