Acqua di Gio is one of those fresh, sporty fragrances that lingers, both in terms of its longevity and in that it stays with you even when you aren't wearing it. Splash some on a tester card and its sharp, fruity-citrus smell will park itself firmly in your mind, urging to you to buy some. Of course, that's only if you like the combination of bergamot, green tangerine, jasmine petal and rosemary, but if you do then it's pretty much a must-have scent.
The odour it produces also remains very true right through its wearing cycle, with little change as it ages (on my skin, at least.) The only point I'd make is that I don't think it's as `aqua' as its name suggests, in fact I'd instead call it very much a `green' scent, but I guess that wouldn't have looked as good on the bottle.
Acqua is also one of those fragrances that a lot of men seem to wear, both on nights out or just around town. I'm not sure whether that's true, or if it's just the result of it being a slightly generic smell, but it will make you feel like you aren't unique (i.e., odd) if you go out wearing it. On the other hand, this popularity may lessen its impact if you're trying to stand out from the crowd, so I tend to use this much less than I do some of my not-so-well-known fragrances, which I'm not as likely to smell on other blokes.