My institution still invests in both. There are some issues with e-books apart from the difference in media:
Restrictions in licenses can mean only one or just a few people can access an e-book at once. Sometimes the library software does not recognise when someone has closed a browser window so the e-book can get locked.
Apart from the restriction on the number of pages that you can print the print quality can be very poor.
In conclusion, e-book usage is currently been driven by economics and perception of customer demand but it will also need to take into account usability and user satisfaction.
Peter, in my institution ebook use is not widespread. And in my opinion, perhaps because my background is from another time, the experience of reading a book, without spending a sheet, does not leave the same taste.