Some fun stuff here, but I did find that it needed much more editing than it seems to have gotten.
Aside from the obvious technical issues and oddness (an obvious problem when you have a non-techie writer writing about technically inclined characters, but he should have had someone with a clue heavily edit the technese sections just so they read right, rather than getting a concept and wordlist (or whatever) from someone techish and then going off on his own without an apparent safety net), the plot seems to have some discontinuity issues, and other things that are never, or badly, explained.
For staters...it's clear that Saskia was created by Leviathan. But it's not at all clear who created Suzi (who seems to date from after Librarius broke loose), nor why Lib wants revenge on Aaron and Jackson in the first place -- it fits with his cover story (which one?), but going to that much effort for the cover doesn't feel right.
Basically, Lib seems to have been invented to make sure the Wordwood would not have gone bad after all, but his inclusion doesn't seem to make that much sense, and the shifting stories doesn't help all that much.
In general, De Lint does do a good job keeping up with a complicated plot where everyone's actions seem to end up being someone else's problem, but he does seem to lose track of things occasionaly, and his inability to believably write about tech in a tech book hurts him a lot.