Linkdeathbought one of these when i went to milan last year, still using the book that came with it in the first place. unfortunately, there tends to be a lot of bleed through and feathering. Im using noodler's inks (Warden series and Red-Black), on EF and F nibbed pens.
you can of course, get a better notebook from rhodia or clairefontaine, so long as its A5, and no more than 4 cm thick, you can replace the stock one.