It's so great that they opened the Copley location since Faneuil Hall is a bit inconvenient for most people. The biggest disadvantage here is that, unlike New York City, many of the Boston venues are spread out (so if you really wanted to do something last minute, you might have to still haul yourself over the Cambridge to see a show). WIth ticket prices so high, this is a great resource. There rarely seems to be a line (unlike NYC). ArtsBoston runs the booth, so you can always order discounted tix ahead of time online (though they don't guarantee tix, I've ordered many things over the years and have always gotten my first choice and always gotten a ticket, which they mail to you). Their website also tells you about Bostix availability for the day, too (so no mystery when you arrive).