Carnegie Mellon and the other universities, world-wide, are rightly receiving accolades in the press for the fact that the Universal Digital Library has exceeded its target by having digitised 1,500,000 volumes.
However, the UDL is not without its problems. For example, you need to download and install a viewer - either DjVu (of which I've heard) or the Tiff viewer - of which I'd never heard. Still, I downloaded the latter and then found that it appears to call up Quicktime actually to view the pages - all of them being images, rather than transcriptions. Needless to say, this is rather slow.
Also, I found that not all of the items are 100% open access. For example, I went looking for something on the history of Alsace (having a friend there who grows some excellent wines :-) and found that only 15% of Townroe's A Wayfarer in Alsace is actually available - and it ends in the middle of a chapter; in fact in the middle of a sentence!
Then there's the problem of blank pages being digitised. I located Hazen's Alsace-Lorraine under German Rule and found that the first seven pages were blank, so I skipped to the end and found blank pages from page 262 to 268. However, I persevered, and found text on page 261, so I skipped back to the start and found the start of the text on page 8. I image that others, not as determined as I might give up!
As for printing, you have a choice - you can print either the whole file or the current page and, because the files are all pictures, you can't select text for quoting. And there's no search function within a file.
Clearly digital library technology has a long way to go before it becomes user-friendly and the Universal Digital Library seems to have futher to go than many.