Dutch website n1ntendo.nl got their pre-release copy of The Legend of Zelda: A Link Between Worlds and have played it constantly since then, they report in a recent post.
They also claim that The Legend of Zelda: A Link Between Worlds lasts around 18 and a half hours in playtime. This 18 and a half hours is not just for the initial story mode, but for 100% completion, which includes getting all the weapon upgrades, heart pieces, and completing all the side quests.
18 and a half hours of Zelda will keep 3DS gamers busy for some time. If that playtime is correct, A Link Between Worlds is only slightly shorter than the average for other portable Zelda titles.
The Legend of Zelda: A Link Between Worlds will be released November 22nd. Check out some gameplay footage of A Link Between Worlds here.