I first read Silverwing when I was quite young; I remember being completely enraptured with the world of the Silverwing bats. They are quite an under-appreciated creature, and as a life-long lover of them I was thrilled to see a series dedicated just to bats. Being able to 'see' though their eyes was a brilliant addition - bats don't see in colour, and not once does Oppel mention any.
The story could be considered quite predictable and rather unremarkable at times, however, it's a book that I'd recommend reading to anyone interested in this sort of fantasy.