i've just started playing it myself, though it doesn't seem like an ultra long RPG. "long enough" is just about how long i'd say it is. (i would approximate that i'm around a quarter of the way through it)
whenever i would rent games as a kid, i'd be like "earthbound.. that looks pretty cool.." but i'd always end up picking something else. now that i'm finally playing it (on an emulator
) it's pretty damn cool.