I suspect "better" means "more books", not "more usable as an institution".

The Library of Congress has closed stacks - which isn't surprising, considering how many books it has; but they do assign qualified scholars and grad students part of a shelf (errrr, it's a shelf-per-person, not one shelf for all) near the circulation desk, where you can keep the books you've "checked out" for quite a while. It's a good compromise: the books have to stay within the building, but its remarkably easy for you to access the books you need over a period of time.

. . . and there's the other method: build your own. Too bad it's bloody expensive.