[GeoffR]

My library (Auckland, NZ) has OverDrive and BorrowBox, the BorrowBox collection is smaller but it includes some publishers (such as Macmillan) which are were missing from OverDrive, so the collections complement each other somewhat. Edit: Actually now I check I see that Macmillan books are on OverDrive too, so perhaps the collections have more overlap now.

BorrowBox settings at my library are: 10 ebook + 10 audiobook loans, fixed 28 day loan period, but early returns permitted (but it doesn't seem to work with all books?) The Borrowbox collection is currently about 11,000 ebooks and 2,000 audiobooks.