You'll find that most Forge World rules are terribly unbalanced against the player using them; that is to say, they're not very good and often give your opponent the advantage. However, if you don't care about that, then use the list to your heart's content.
What you'll need to consider is that it's a Guard army list written without the benefit of the new Guard Codex. This means it has a lot more in common with the previous Guard Codex than the new one. Of course, that may have
changed, but I've not had time to go over those updates.