They are definitely worth the read, just give yourself some time. Maybe I'm just a slow reader, but it took me a long time to finish my first 1000 page book.
£10 is a great deal. New they would have been four or five times that for the paperback and ten times that for the hardcover.
There is a prequel novel,
New Spring and a couple of novellass, as well to read if you really get into it.